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Editorial: Think irritable bowel syndrome when treating overactive bladder

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The bladder and bowel are functionally related organs; they lie in close proximity, have similar innervations and some structural similarities, albeit having different functional characteristics; they are both critical for the storage, collection and expulsion of waste products. Several previous clinical reports have suggested that LUTS, such as overactive bladder syndrome (OAB), can occur concurrently with disorders of the colon, such as irritable bowel syndrome (IBS).

In the study entitled ‘Relationship between overactive bladder and irritable bowel syndrome: a large-scale internet survey in Japan using the overactive bladder symptom score and Rome III criteria’, Matsumoto et al. investigate the prevalence of OAB and IBS in Japan using a large scale internet based survey. In all, 10 000 randomly selected participants completed the surveys with equal numbers of men and women. Subjects were grouped according to age and gender and the prevalence and severity of OAB was assessed using the OAB symptom score (OABSS). The OABSS as an assessment tool combines OAB symptoms into a single score. Four main criteria were examined (daytime frequency, night-time frequency, urgency and urgency incontinence) and disease severity was assessed by overall score value (5, mild; 6–11, moderate; and >12 severe). Similar epidemiological studies have been conducted in the past; however, this is the first study to use the OABSS to assess OAB in a general population. IBS was assessed using the IBS module of the ROME III criteria.

The study found that in the population studied, the overall prevalence of OAB was 9.3% (with 9.7% of men and 8.9% of women affected) and increased with advancing age. Of those affected, 59% reported mild symptoms, 40% reported moderate symptoms and 1% reported sever symptoms. The prevalence of IBS was greater, with 21.2%  of people reporting symptoms (18.6% of men and 23.9% of women); however, conversely the incidence of IBS was reduced with age. Consistent with previous epidemiological studies conducted in Europe and the USA, 33.3% of participants reporting OAB symptoms also had concurrent IBS (32.0% men and 34.8% women), interestingly though, the prevalence of concurrent IBS and OAB was unaffected by age, suggesting that age is not a contributing factor to this relationship.

The exact aetiology of OAB and IBS, by virtue of the non-specific nature of both symptom syndromes, cannot be clearly defined. However, both disorders are characterised by at least increased frequency of visceral emptying due to increased sensation and in many cases motor hyperactivity. In the LUT this takes the form of urgency with associated detrusor overactivity in 40–90% of patients and in the bowel it manifests as pain and discomfort. Experimental studies in rodent models have shown that initiation of bladder overactivity using chemical agents, such as cyclophosphamide, can induce hypersensitivity of the colon and conversely induction of colitis can lead to altered bladder function resembling OAB (Bielefeldt K et al., Brumovsky PR et al., Pezzone MA et al.). The concurrence of these disorders suggests that there may be a common underlying pathology or dysfunction at least in a subset of patients.

One theory put forward to explain the concurrence of OAB and IBS is that of cross-organ sensitisation, whereby sensory innervation of the bladder and bowel interact. These interactions can occur at multiple levels. In the periphery, there is evidence for afferent fibres, which extensively branch and innervate multiple target structures. These dichotomising afferents converge at a single neurone in the dorsal root ganglion (DRG). Studies using retrograde tracers injected into the colon and bladder wall have identified specific DRGs neurones that receive projections from both organs, although the numbers or these neurones are low. Sensitisation of the endings in one organ by local inflammation damage or injury would probably impact on overall sensitivity after upregulation in excitability in all terminal receptive fields.

In addition to peripheral mechanisms, sensitisation of central pathways could also be a contributing factor in cross-organ sensitisation. Spinal neurones receiving afferent input from the bladder have been shown to respond to afferent input from other pelvic structures including the colon. Second-order neurones in the spinal cord therefore receive convergent input from various visceral structures, as well as somatic inputs. This theory provides an explanation for the phenomenon of referred pain, where sensations from the viscera are experienced in the associated somatic sensory fields. Such viscero-somatic convergence has been extensively investigated (the most common example of this is angina), but only recently has viscero-visceral referral received attention. Clearly much research is still required to understand these interactions; however; this study clearly highlights the concurrence of bladder and bowel disorders. Understanding the mechanism(s) involved could have important implications for future therapeutic interventions aimed at treating both OAB and IBS.

Donna Daly and Christopher Chapple*

Department of Biomedical Science, University of Sheffeld and *Department of Urology, The Royal Hallamshire Hospital, Sheffeld Teaching Hospitals NHS Foundation Trust, Sheffield, UK

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Article of the week: Nomogram helps the preoperative prediction of early biochemical recurrence after radical prostatectomy

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Every week the Editor-in-Chief selects the Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an accompanying editorial written by a prominent member of the urological community. This blog is intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation.

Finally, the third post under the Article of the Week heading on the homepage will consist of additional material or media. This week we feature a video of Ángel Borque discussing his paper.

If you only have time to read one article this week, it should be this one.

Genetic predisposition to early recurrence in clinically localized prostate cancer

Ángel Borque, Jokin del Amo†, Luis M. Esteban*, Elisabet Ars§, Carlos Hernández**, Jacques Planas, Antonio Arruza††, Roberto Llarena‡, Joan Palou§, Felipe Herranz**, Carles X. Raventós, Diego Tejedor†, Marta Artieda†, Laureano Simon†, Antonio Martínez†, Elena Carceller, Miguel Suárez, Marta Allué, Gerardo Sanz* and Juan Morote

‘Miguel Servet’ University Hospital, *University of Zaragoza, Zaragoza, Spain, †Progenika Biopharma S.A., ‡University Hospital of Cruces, Bilbao, §Puigvert Foundation, ‘Vall d’Hebron’ University Hospital, Barcelona, **‘Gregorio Marañón’ University Hospital, Madrid, and ††Hospital of Txagorritxu, Vitoria, Spain

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OBJECTIVES

• To evaluate genetic susceptibility to early biochemical recurrence (EBCR) after radical prostatectomy (RP), as a prognostic factor for early systemic dissemination.

• To build a preoperative nomogram to predict EBCR combining genetic and clinicopathological factors.

PATIENTS AND METHODS

• We evaluated 670 patients from six University Hospitals who underwent RP for clinically localized prostate cancer (PCa), and were followed-up for at least 5 years or until biochemical recurrence.

• EBCR was defined as a level prostate-specific antigen >0.4 ng/mL within 1 year of RP; preoperative variables studied were: age, prostate-specific antigen, clinical stage, biopsy Gleason score, and the genotype of 83 PCa-related single nucleotide polymorphisms (SNPs).

• Univariate allele association tests and multivariate logistic regression were used to generate predictive models for EBCR, with clinicopathological factors and adding SNPs.

• We internally validated the models by bootstrapping and compared their accuracy using the area under the curve (AUC), net reclassification improvement, integrated discrimination improvement, calibration plots and Vickers’ decision curves.

RESULTS

• Four common SNPs at KLK3, KLK2, SULT1A1 and BGLAP genes were independently associated with EBCR.

• A significant increase in AUC was observed when SNPs were added to the model: AUC (95% confidence interval) 0.728 (0.674–0.784) vs 0.763 (0.708–0.817).

• Net reclassification improvement showed a significant increase in probability for events of 60.7% and a decrease for non-events of 63.5%.

• Integrated discrimination improvement and decision curves confirmed the superiority of the new model.

CONCLUSIONS

• Four SNPs associated with EBCR significantly improved the accuracy of clinicopathological factors.

• We present a nomogram for preoperative prediction of EBCR after RP.

 

Read Previous Articles of the Week

Editorial: Prostate cancer families – predicting disease before and after the radical

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In this issue of BJUI, Borque et al. discuss a subject that is now very close to my heart. Aged 48 years, I am 6 weeks post radical prostatectomy for a Gleason 3 + 4 prostate adenocarcinoma measuring ~2 mL in volume, with a PSA level of 2.54 ng/mL. Histology reassures me it is organ confined and seminal vesicle negative. My father and his brother both died aged 63 years of Gleason 10 prostate cancer and my brother is awaiting his radical prostatectomy in a few weeks. I have two sons, one of whom has asked me when he should be tested. Any prognostic information is going to help me advise my family.

In all, 85% of prostate cancers appear to be sporadic. The incidence of all prostate cancers is 1 in 8500 under the age of 40 years, rising to 1 in 15 at 60–69 years and 1 in 8 after that. The lifetime risk in the UK for all men is 8–10%.

The genetics of prostate cancer are confused by case clustering; the family members of men with a prostate cancer diagnosis seek out early advice from their physician resulting in detection of some clinically questionable cancers and an apparent higher incidence in certain families. These families do not necessarily have genetically determined prostate cancer.

The lifetime risk is altered dramatically by having two or more first-degree relatives with a diagnosis of prostate cancer; if the disease in the relative is identified before the age of 65 years the risk is increased further. Bratt suggests the risk rises from 15 to 20% when a single first-degree relative is diagnosed aged < 60 years. Zeegers et al., in a meta-analysis, have shown that diagnosing prostate cancer in a relative aged < 65 years increases the relative risk of having prostate cancer by 3.3, and having two first-degree relatives increases the relative risk by a factor of 5.1.

Analysis of a huge database from Sweden including data on 182 000 fathers and 3700 sons with prostate cancer suggest a standardised incidence ratio of 9.4 in men with a father and brother diagnosed with prostate cancer, with further analysis also showing unsurprisingly that the risk increases as an individual ages. Some true ‘prostate cancer families’ have been identified. These families have three or more relatives with prostate cancer often associated with a diagnosis at a young age, possibly with an increased tendency to an aggressive
phenotype; my uncle was 18 months from diagnosis to death from his disease, my father 4 years. In these families, the relative risk in male family members is 3.39 in those where the diagnosis of identified sufferers was made aged > 65 years, and 7.33 where the diagnosis is in men aged < 65 years. These risks which effectively give a lifetime risk in the individual of 45–50% are associated with carriage of a gene identified as increasing the prostate cancer risk. The best identified of these genes is the BRCA2 (breast cancer type 2 susceptibility protein) gene, which is associated with an increased risk of other cancers including breast, ovarian, gallbladder and pancreatic cancer, as well as malignant melanoma. This gene, carried in 1% of
Ashkenazi Jewish families, is associated with prostate cancer families in this population.

Now my prostate has been removed, I need to determine my chance of treatment failure. It would be interesting to know whether my genes and my single nucleotide polymorphisms (SNPs), which have almost certainly been responsible for me developing prostate cancer, can also predict my chance of developing early biochemical recurrence (EBCR) and the possibility of needing further treatment. In the Borque et al. article, I would appear on the first model (Fig. 1) to have a chance of ECBR of between 1 and 5%. This risk, according to this study, could increase to up to 30%, if I was to have four SNPs associated with prostate cancer (Fig. 2). Furthermore, we need to know whether identification of SNPs is any better than other possible predictors of EBCR and disease progression, such as the identification of lymphovascular invasion and tumour volume in the final specimen and the presence of extraprostatic extension, data not included in this study. Incidentally, I had no evidence of lymphovascular invasion.

The authors identify that this study needs repeating, particularly in a more ethnically diverse group (this study included Caucasian origin as an entry criterion), and we await longer term data to see how SNPs predict metastasis and prostate cancer-related death.

Jonathan M. Glass
Department of Urology, Guys & St Thomas’ Hospital Trust, London, UK

Read the full article

Video: Genetic predisposition to early recurrence in clinically localized prostate cancer

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Genetic predisposition to early recurrence in clinically localized prostate cancer

Ángel Borque, Jokin del Amo†, Luis M. Esteban*, Elisabet Ars§, Carlos Hernández**, Jacques Planas, Antonio Arruza††, Roberto Llarena‡, Joan Palou§, Felipe Herranz**, Carles X. Raventós, Diego Tejedor†, Marta Artieda†, Laureano Simon†, Antonio Martínez†, Elena Carceller, Miguel Suárez, Marta Allué, Gerardo Sanz* and Juan Morote

‘Miguel Servet’ University Hospital, *University of Zaragoza, Zaragoza, Spain, †Progenika Biopharma S.A., ‡University Hospital of Cruces, Bilbao, §Puigvert Foundation, ‘Vall d’Hebron’ University Hospital, Barcelona, **‘Gregorio Marañón’ University Hospital, Madrid, and ††Hospital of Txagorritxu, Vitoria, Spain

Read the full article

• To evaluate genetic susceptibility to early biochemical recurrence (EBCR) after radical prostatectomy (RP), as a prognostic factor for early systemic dissemination.

• To build a preoperative nomogram to predict EBCR combining genetic and clinicopathological factors.

PATIENTS AND METHODS

• We evaluated 670 patients from six University Hospitals who underwent RP for clinically localized prostate cancer (PCa), and were followed-up for at least 5 years or until biochemical recurrence.

• EBCR was defined as a level prostate-specific antigen >0.4 ng/mL within 1 year of RP; preoperative variables studied were: age, prostate-specific antigen, clinical stage, biopsy Gleason score, and the genotype of 83 PCa-related single nucleotide polymorphisms (SNPs).

• Univariate allele association tests and multivariate logistic regression were used to generate predictive models for EBCR, with clinicopathological factors and adding SNPs.

• We internally validated the models by bootstrapping and compared their accuracy using the area under the curve (AUC), net reclassification improvement, integrated discrimination improvement, calibration plots and Vickers’ decision curves.

RESULTS

• Four common SNPs at KLK3, KLK2, SULT1A1 and BGLAP genes were independently associated with EBCR.

• A significant increase in AUC was observed when SNPs were added to the model: AUC (95% confidence interval) 0.728 (0.674–0.784) vs 0.763 (0.708–0.817).

• Net reclassification improvement showed a significant increase in probability for events of 60.7% and a decrease for non-events of 63.5%.

• Integrated discrimination improvement and decision curves confirmed the superiority of the new model.

CONCLUSIONS

• Four SNPs associated with EBCR significantly improved the accuracy of clinicopathological factors.

• We present a nomogram for preoperative prediction of EBCR after RP.

Article of the week: The survey says: surgeon preferences during robot-assisted radical prostatectomy

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Every week the Editor-in-Chief selects the Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an accompanying editorial written by a prominent member of the urological community. This blog is intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation.

If you only have time to read one article this week, it should be this one.

The European Association of Urology Robotic Urology Section (ERUS) survey of robot-assisted radical prostatectomy (RARP)

Vincenzo Ficarra1, Peter N. Wiklund2, Charles Henry Rochat3, Prokar Dasgupta4, Benjamin J. Challacombe4, Prasanna Sooriakumaran5, Stefan Siemer6, Nazareno Suardi7, Giacomo Novara1 and Alexandre Mottrie8

1Oncological and Surgical Sciences, Urology Clinic, University of Padua, Padua, Italy; 2Urology Laboratory, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; 3Multidisciplinary Centre of Robot-Assisted Laparoscopic Surgery, Générale-Beaulieu Clinic, Geneva, Switzerland; 4Department of Urology, Guy’s Hospital, London, UK; 5Department of Urology, Royal Surrey County Hospital, Guildford, UK; 6Department of Urology, Universitätsklinikum des Saarlandes, Homburg/Saar, Germany; 7Department of Urology, Vita-Salute University San Raffaele, Milan, Italy; and 8Department of Urology O.L.V. Clinic Aalst, Aalst, Belgium; EAU Robotic Urologic Section (ERUS) Scientific Working Group

Read the full article
OBJECTIVE

• To evaluate surgeons adherence to current clinical practice, with the available evidence, for robot-assisted radical prostatectomy (RARP) and offer a baseline assessment to measure the impact of the Pasadena recommendations. Recently, the European Association of Urology Robotic Urology Section (ERUS) supported the Pasadena Consensus Conference on best practices in RARP.

SUBJECTS AND METHODS

• This survey was performed in January 2012. A specific questionnaire was sent, by e-mail, to 145 robotic surgeons who were included in the mailing-list of ERUS members and working in different urological institutions.

• Participating surgeons were invited to answer a multiple-choice questionnaire including 24-items evaluating the main RARP surgical steps.

RESULTS

• In all, 116 (79.4%) invited surgeons answered the questionnaire and accepted to participate to the ERUS survey.

• In all, 47 (40.5%) surgeons performed >100 RARPs; 41 (35.3%) between 50 and 100, and 28 (24.1%) <50 yearly.

• The transperitoneal, antegrade technique was the preferred approach.

• Minimising bladder neck dissection and the use of athermal dissection of the neurovascular bundles (NVBs) were also popular.

• There was more heterogeneity in the use of energy for seminal vesicle dissection, the preservation of the tips of the seminal vesicle and the choice between intra- and interfascial planes during the antero-lateral dissection of the NVBs. There was also large variability in the posterior and/or anterior reconstruction steps.

CONCLUSIONS

• The present study is the first international survey evaluating surgeon preferences during RARP.

• Considering that the results were collected before the publication of the Pasadena recommendations, the data might be considered an important baseline evaluation to test the dissemination and effects of the Pasadena recommendations in subsequent years.

 

Read Previous Articles of the Week

Editorial: Robot-assisted radical prostatectomy: getting your ducks in a row!

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Robot-assisted radical prostatectomy (RARP) has become the technique of choice for clinically localised prostate cancer. However, marked inter-surgeon heterogeneity and an obvious lack of standardisation exist for the indications and technique of the procedure. In this issue of the BJUI, Ficarra et al. conducted a multinational survey seeking opinion from 145 robotic surgeons about individual practices during RARP. These opinions can be compared against the benchmark set by the Pasadena Consensus and can help gauge the impact of its recommendations.

Responses from 116 (79.4%) invited surgeons were analysed. The authors acknowledge the limited participation of non-European surgeons (17.1%), which may limit validity and application of its results at a global level. Most surgeons were in consensus with the Pasadena recommendations for transperitoneal access (88%), antegrade approach (76%) and bladder neck preservation (77%). The opinions on cautery use for the seminal vesicle/vas deferens dissection (51% athermal; 21% bipolar), athermal nerve-sparing approach (90%) and the use of the running suture technique for urethrovesical anastomosis (96.6%) were also in agreement.

Despite wide surgeon and institutional variability regarding the definition of bladder neck preservation and its role in the return of urinary continence, most preferred to preserve the bladder neck. This may pose difficulty in the interpretation of the results in view of the ambiguity about the definition and technique adopted under the term ‘bladder neck preservation’ (Eur Urol, BJU Int).

Most of the participating surgeons were using anterolateral prostatic fascia dissection (Veil of Aphrodite) towards preserving the cavernous nerves by using an athermal approach. Over the last decade the evolution of robot-assisted surgery, with excellent three-dimensional visualisation, depth perception, and EndoWrist® technology has made working in the confines of the pelvis both ubiquitous and a desired skill.

The present study found that 33% of surgeons omitted the internal iliac lymph nodes (LNs) and removed only obturator, with or without the external iliac LNs. The Pasadena Consensus recommends a template that includes the internal iliac, external iliac and obturator LNs. Mattei et al. in an attempt to map primary prostatic lymphatic ‘landing’ zones found that after performing a standard limited LN dissection (dorsal to and along the external iliac vein; medially along the obturator nerve) only 38% of LNs were removed. They recommended a template that retrieves LNs extending up to the ureteric crossing of the common iliac vessels. Meanwhile, Menon et al. evaluated the role of only internal iliac LN dissection (limited) in patients with a low probability of nodal disease (Partin table prediction 0–1%), and surprisingly found positive LNs in the internal iliac/obturator region 13.7 times more often than in the external iliac/obturator region. One of the issues that could be addressed in future surveys would be to evaluate how surgeons view and adapt to changes in the proposed LN template. The Pasadena Consensus further recommends considering performing LN dissection for the low-risk category based on the D’Amico risk stratification. The surgeon’s indications for pelvic LN dissection were not addressed in this survey.

Despite significant studies, including two randomised controlled trials (RCTs), published in the peer-reviewed literature reporting minimal advantage for early recovery of urinary continence with posterior reconstruction, a significant number of the surveyed surgeons still preferred to perform it. Responses to other questions about the posterior/anterior reconstruction also showed marked variability reflecting the controversial opinion about the value of these surgical steps.

On the other hand, future surveys should gather opinions about the role of RARP for high-risk disease, standardised evaluation of surgical complications; while addressing continence and potency status along with methods of their measurement. These topics were already addressed in the Pasadena Consensus and obtaining opinions of surgeons will further provide insight as to how surgeons adapt to the ever-changing advances in this field.

Over the last decade RARP has gained acceptance despite the absence of high-quality RCTs in robot-assisted surgery. The Pasadena Consensus was meant to meet the need for uniformity and this study educates us on how the surgeons really perform ‘in the trenches’. Until further evidence is available, surgeon experience and institutional volume will remain the main force driving the use of these surgical techniques and their outcomes.

Ahmed A. Aboumohamed and Khurshid A. Guru
Department of Urology, Roswell Park Cancer Institute, Buffalo, NY, USA

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Article of the week: Calcium : citrate ratio may predict severe lithogenesis

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Every week the Editor-in-Chief selects the Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an accompanying editorial written by a prominent member of the urological community. This blog is intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation.

Finally, the third post under the Article of the Week heading on the homepage will consist of additional material or media. This week we feature a video of Miguel Angel Arrabal-Polo discussing his paper.

If you only have time to read one article this week, it should be this one.

Importance of citrate and the calcium : citrate ratio in patients with calcium renal lithiasis and severe lithogenesis

Miguel Angel Arrabal-Polo*, Miguel Arrabal-Martin*,  Salvador Arias-Santiago**†, Juan Garrido-Gomez‡, Antonio PoyatosAndujar§ and Armando Zuluaga-Gomez**

Department of Urology, San Cecilio University Hospital, **Department of Medicine, Baza Hospital, †Department of  Medicine, University of Granada, and ‡Departments of Traumatology and §Biochemistry, San Cecilio University Hospital, Granada, Spain

Read the full article
OBJECTIVE

• To analyse the importance of urinary citrate and the urinary calcium : citrate  ratio in patients with calcium renal lithiasis and severe lithogenesis compared with  a control group of patients without lithiasis.

MATERIAL AND METHODS

• A cross-sectional study of 115 patients in eastern Andalusia, Spain was conducted.

• The patients were divided into two groups: Group A: 56 patients aged 25 – 60 years without calcium renal lithiasis; Group B: 59 patients aged 25 – 60 years, presenting with calcium renal lithiasis and severe lithogenesis.

• The citrate levels and the calcium : citrate ratio in the patients’ urine and the relationship of these two factors to lithiasic activity were analysed and compared.

RESULTS

• In Group B, 32.2% of the patients presented with hypocitraturia, compared with 14.3% of the patients in Group A (P = 0.02).

• The urinary citrate levels were lower in Group B than in Group A (P = 0.001) and the calcium : citrate ratio was higher in Group B than in Group A (P = 0.005).

• The results suggest that a patient urinary calcium : citrate ratio > 0.25 indicates severe lithogenesis (with a sensitivity of 89% and a specifi city of 57%).

• After linear regression analysis, we found that the urinary citrate level is an independent factor associated with the changes in bone densitometry T-score values of patients.

CONCLUSIONS

• The patients with severe lithogenesis presented with hypocitraturia, which was associated with lower bone mineral density.

• The calcium : citrate ratio, which is linearly related to the bone resorption marker β-crosslaps, could be useful in evaluating the risk of severe lithogenesis when this ratio is > 0.25.

 

Read Previous Articles of the Week

Editorial: The importance of citrate in patients with calcium stones and loss of bone mineral density

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Stone disease and osteopaenia are both common conditions, and reduced bone mineral density (BMD) is an increasingly recognized complication in stone formers; indeed, in a previous paper in BJUI, Arrabal-Polo et al. reported that patients with recurrent stones have lower BMD compared with controls or patients with just a single episode of urolithiasis.

Although the exact pathogenesis of bone loss in stone disease is yet to be determined, the conceptually obvious relationship with hypercalciuria is well documented. In the present study, Arrabal-Polo et al. emphasise that hypocitraturia is also associated with reduced BMD. Furthermore, they found a higher calcium : citrate ratio in patients with a cumulative maximum stone diameter > 20 mm, or in those with frequent recurrences than in controls, and found that this correlated with higher levels of β-crosslaps, consistent with increased bone resorption in these patients.

We commented in our previous editorial that metabolic abnormalities should be sought in recurrent stone formers, and managed in a multi-disciplinary setting. In addition to dietary advice, options for treatment include bisphosphonates (which inhibit bone resorption, and are commonly used in osteoporosis), thiazide diuretics (which reduce calcium excretion and can increase BMD) and potassium citrate (which acts as an alkalinizing agent mitigating the bone restorative effect of acidosis). This approach is supported by recent data in medullary sponge kidneys, in which hypercalciuria and hypocitraturia were commonly detected in association with reduced BMD. Patients who were treated with potassium citrate were found to have increased urinary pH citrate levels, and an improvement in their BMD.

In the present article, Arrabal-Polo et al. suggest using a calcium : citrate ratio of 0.25 for predicting the risk of future recurrent stone formation, but this value could equally be used to predict the risk of patients having reduced BMD and the complications that may follow. Either way, their findings strengthen the argument for metabolic screening of recurrent stone formers, and for an assessment of these patients’ BMD. Patients can then be appropriately treated with a thiazide diuretic, potassium citrate, or a bisphosphonate, either singly or in combination, according to the abnormalities detected and their progress on treatment.

Daron Smith
Stone and Endourology Unit, University College Hospital, London, UK

Chris Laing
UCL Centre for Nephrology, Royal Free Hospital London, London, UK

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Video: Commentary by Dr Arrabal-Polo on the calcium : citrate ratio.

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Importance of citrate and the calcium : citrate ratio in patients with calcium renal lithiasis and severe lithogenesis

Miguel Angel Arrabal-Polo*, Miguel Arrabal-Martin*,  Salvador Arias-Santiago**†, Juan Garrido-Gomez‡, Antonio PoyatosAndujar§ and Armando Zuluaga-Gomez**

Department of Urology, San Cecilio University Hospital, **Department of Medicine, Baza Hospital, †Department of  Medicine, University of Granada, and ‡Departments of Traumatology and §Biochemistry, San Cecilio University Hospital, Granada, Spain

Read the full article
OBJECTIVE

• To analyse the importance of urinary citrate and the urinary calcium : citrate  ratio in patients with calcium renal lithiasis and severe lithogenesis compared with a control group of patients without lithiasis.

MATERIAL AND METHODS

• A cross-sectional study of 115 patients in eastern Andalusia, Spain was conducted.

• The patients were divided into two groups: Group A: 56 patients aged 25 – 60 years without calcium renal lithiasis; Group B: 59 patients aged 25 – 60 years, presenting with calcium renal lithiasis and severe lithogenesis.

• The citrate levels and the calcium : citrate ratio in the patients’ urine and the relationship of these two factors to lithiasic activity were analysed and compared.

RESULTS

• In Group B, 32.2% of the patients presented with hypocitraturia, compared with 14.3% of the patients in Group A (P = 0.02).

• The urinary citrate levels were lower in Group B than in Group A (P = 0.001) and the calcium : citrate ratio was higher in Group B than in Group A (P = 0.005).

• The results suggest that a patient urinary calcium : citrate ratio > 0.25 indicates severe lithogenesis (with a sensitivity of 89% and a specificity of 57%).

• After linear regression analysis, we found that the urinary citrate level is an independent factor associated with the changes in bone densitometry T-score values of patients.

CONCLUSIONS

• The patients with severe lithogenesis presented with hypocitraturia, which was associated with lower bone mineral density.

• The calcium : citrate ratio, which is linearly related to the bone resorption marker β-crosslaps, could be useful in evaluating the risk of severe lithogenesis when this ratio is > 0.25.

Article of the week: Prolonged SNM testing effective despite bacteria presence

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Every week the Editor-in-Chief selects the Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an accompanying editorial written by a prominent member of the urological community. This blog is intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation.

If you only have time to read one article this week, it should be this one.

Prolonged percutaneous SNM testing does not cause infection-related explanation

Bastian Amend, Jens Bedke, Mahmoud Khalil, Arnulf Stenzl and Karl-Dietrich Sievert

Department of Urology, Eberhard Karls University Tuebingen, Tuebingen, Germany

Read the full article
OBJECTIVE

• To evaluate the impact of prolonged stage 1 testing on bacterial electrode colonization, infection and treatment success.

MATERIALS AND METHODS

• In all, 21 patients who underwent sacral neuromodulation (SNM) for periods 1 month were prospectively evaluated; nine patients had overactive bladder syndrome (OAB), 10 had urinary retention, two had faecal incontinence (FI), and 13 had diabetes and overweight/obesity.

• After stage 1 testing electrode extension leads were microbiologically analysed to assess bacterial colonization.

• The primary measurements were pre- and post-SNM treatment comparisons based on patient-agreed criteria using an increased 70% minimum improvement rate; secondary measurements were bacterial colonization and impact of infection.

RESULTS

• The mean stage 1 evaluation period was 52.3 days; 16 patients (76%) progressed to stage 2, and five patients were explanted due to inadequate improvement (<70%).

• There was bacterial colonization in 42.9% of patients and 38.2% of extension leads.

• Stage 2 patients showed no infection or wound-healing disorders at a mean follow-up of 33.9 months.

• The success rate for stage 2 implantation treatment was 94%.

CONCLUSIONS

• There are few studies in the literature evaluating SNM testing periods vs the risk of clinically relevant implant infection rates. The present study shows that prolonged testing could potentially enhance treatment efficacy without infection-related explantations of the chronic implant, despite the identification of bacteria.

• SNM-implanted patients with diabetes mellitus or obesity should be followed closely.

• Clinicians might consider using prolonged testing under everyday conditions.

• Prolonged SNM stage 1 testing is a very effective minimally invasive treatment option to evaluate pelvic-related dysfunction.

 

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