This was a retrospective study of patients with a diagnosis of BPH with and without renal failure who underwent treatment in the Department of Urology, after obtaining Ethical Committee approval from Nizam’s Institute of Medical Sciences between January 2015 to December 2016. A total of 60 (sample size was not significant as all the patients who presented with renal failure, i.e., 30, to our institute during the study period were included in the study) patients with a diagnosis of BPH who underwent treatment were taken into the study. Thirty patients had renal failure at the presentation and another 30 patients with diagnosis of BPH without renal failure were also taken into the study for comparison.

All patients were evaluated with detailed clinical history about age, type and duration of voiding symptoms, IPSS score, and the comorbid illnesses were recorded. Physical examination including DRE was done and the findings were noted. Patients with urinary retention were noted and volume of urine drained from the bladder was recorded. Laboratory examination included serum electrolytes, blood urea serum creatinine, complete haemogram and urine examination, including bacterial cultures were performed. Uroflowmetry was done if the patient was not in retention and followed by ultrasound abdomen to look for upper tracts for presence and degree of hydronephrosis, bladder for any distension and wall thickening, prostate for size and echotexture and to record postvoid residual urine volumes if the patient is not on per urethral catheter. Urodynamic study was done in 15 patients with renal failure.

All patients underwent TURP and during the surgery, configuration of the prostate and bladder morphology were recorded. Postoperatively the drop in haemoglobin, any need for blood transfusions, and the time to catheter removal were recorded. Uroflowmetry and USG abdomen for postvoid residual volume were done at the time of discharge on third postoperative day and at one, three months follow up. Serum creatinine was taken as measure of renal function. Serum creatinine at presentation, lowest value after catheterisation, one week after TURP and at one, three months follow up was recorded.

Symptoms duration and IPSS scores analysed with student’s t-test. Fisher’s-exact test was used to analyse comorbid illness, retention of urine, urine volume drained after catheterisation and ultrasound findings. Intraoperative findings like Grade III lateral lobe and median lobe enlargement were evaluated with Chi-square test.

Mean age of BPH patients presenting with renal failure was 66.2 years and 63.4 years in patients without renal failure. Obstructive voiding symptoms were more common in patients with renal failure. The mean duration of symptoms in patients of BPH with renal failure was 22.3 (3-60) months and it was 19.6 (2-54) months in patients without renal failure (p=0.798) [Table/Fig-1]. Diabetes mellitus and/or hypertension were present in 80% (24) of patients with renal failure and in 63.3% (19) of patients without renal failure (p= 0.257) [Table/Fig-1].

Twenty four patients had retention of urine (acute/chronic/ acute or chronic) in renal failure group and in only seven patients without renal failure (p<0.001). The volume of urine drained on catheterisation was more than 1000 mL in 14 patients of BPH with renal failure (p=0.0028). Sixteen patients had UTIs in the renal failure group and in six patients without renal failure (p=0.015) [Table/Fig-2].

Upper tract dilatation was seen in 24 (80%) patients of BPH with renal failure and in 3 (10%) patients without renal failure (p<0.001) [Table/Fig-2]. Uroflowmetry was done in the patients who were not catheterised in both groups and in majority of patients Qmax was less than 10 mL/second as all patients who underwent surgery were only taken into this study. Presence of poor compliance and detrusor overactivity was more common in patients of BPH with renal failure.

Median lobe enlargement was present in 19 (63.3%) patients with renal failure and in 10 (33.3%) patients without renal failure and this was statistically significant (p=0.0389) by Chi-square test [Table/Fig-3]. Weight of the gland resected (32.3 gm vs 33.6 gm) and mean operative time (62 minute vs 68 minute) were similar in patients with or without renal failure. Two patients required blood transfusion in renal failure group and one in patients without renal failure. There were no significant electrolyte abnormalities in both groups.

Majority of patients had increased urinary flow rates after surgery and two patients did not void after removal of catheter initially, one in each group and catheter was again placed and both of them voided after two days. Postvoid residual volumes were decreased to great extent after surgery. Seven had PVR more than 100 mL at discharge in patients with renal failure and only three had PVR more than 100 mL at one month follow up [Table/Fig-4].

Serum creatinine was done at the time of presentation, after one week of catheterisation in patients who were catheterised, before TURP, one week after TURP, and at one month follow up. Serum creatinine was in the range of 1.7-9.2 (mean- 3.2) mg/dL at the time of presentation in 30 patients. Nearly 17 out of 24 patients who were catheterised, serum creatinine came to normal level (<1.5 mg/dL) after one week of catheterisation and in the remaining seven patients, serum creatinine came to normal level in three patients after TURP and showed decreasing trend in other patients. None of them required dialysis either pre or postoperative period. Once obstruction was relieved 23 (76.6%) patients had normal serum creatinine. About 7 (23.3%) patients had renal failure at one month follow up after TURP. All these patients had either diabetes mellitus or hypertension or both. In 3 patients serum creatinine was more than 3.0 mg/dL and all of them had diabetes and hypertension. Four patients had serum creatinine in the range of 1.5 to 3.0 mg/dL and in these patients one had both diabetes mellitus and hypertension and two patients had hypertension alone and one had only diabetes mellitus [Table/Fig-5].

A community based, epidemiological link between BPH and renal failure has only been assessed in a single study which showed 2.4% prevalence of self-reported renal failure related to a prostate condition (9% reported renal failure from any cause) [4]. Another study showed that men presenting for prostate surgery had a 7.7% prevalence of renal failure compared to 3.7% prevalence in age matched men presenting for non prostate surgery [5]. Thus, evidence of renal failure in men with advanced BPH does not simply reflect older age. A meta-analysis of men presenting to an urologist for BPH treatment showed an average of 13.6% (0.3-30%) had renal failure [6]. A recent study by Hong SR et al., shows the incidence of renal failure by 5.9% [7].

In our study, patients were divided into two groups, with one group having renal failure at presentation and other not having renal failure. The age range was similar in both groups and increasing age did not correlate with the presence of renal failure as noted by Neal DE et al., [8]. The mean duration of symptoms in patients of BPH with renal failure was 22.3 months and it was 19.6 months in patients without renal failure.

In our study, majority of patients were severely symptomatic (IPSS score) in both groups as all patients who underwent surgery were only included in this study. 80% of patients who had renal failure had either diabetes mellitus or hypertension or both to that of 63.3% in patients who had no renal failure. However, in the seven patients who had renal failure at one month follow up after surgery, all of them had associated comorbid illnesses. The presence of diabetes mellitus and/or hypertension will have an impact on the recovery of renal function after relieving the obstruction as reported in the literature [7].

Urinary retention is thought to be the dominant mechanism by which BPH can cause renal failure. Acute urinary retention caused by BPH may be responsible for the majority of acute renal failure cases due to obstructive uropathy [9]. It is also possible that some men may present in acute renal failure with acute urinary retention but actually they have underlying chronic renal failure because of prior chronic urinary retention [3]. In our study 80% of patients of BPH with renal failure had retention of urine (acute and/or chronic) when compared to 23.3% in patients without renal failure. More than 1000 mL urine was drained in 46.6% and 16.6% in renal failure patients and patients without renal failure respectively. So retention of urine had significant impact on renal failure at the time of presentation.

Recurrent UTIs may be a contributing factor for renal failure in men with BPH [10]. The diagnosis of UTIs can be easily missed in patients with BPH since the symptoms of BPH and UTIs are similar. In our study 53.3% of patients with renal failure and 20% in patients without renal failure had concurrent UTIs.

Upper urinary tract dilatation was found in approximately 6% of men presenting for surgical treatment of BPH [11]. In our study upper tract dilatation was seen in 80% in renal failure group and in 10% in patients without renal failure, which clearly showed that the presence of upper tract dilatation on ultrasound can predict the presence of renal failure at presentation. Our study also showed presence of bladder wall thickening on ultrasound imaging was also a risk factor for the presence of renal failure at presentation. However, the mean prostate size by transabdominal imaging was similar in both groups.

Urodynamic studies can be used to identify low bladder compliance and detrusor overactivity both of which have been associated with renal failure [3,12]. In our study, urodynamic study was done in 15 patients, four had only high detrusor voiding pressures and three had acontractile/hypocontractile detrusor with poor bladder compliance and eight patients had combination of high detrusor voiding pressures, detrusor overactivity and poor compliance. So presence of detrusor overactivity and poor compliance along with obstruction is a significant risk factor for renal failure in BPH.

Effect of prostatic configuration on the presence of renal failure in patient of BPH was not mentioned in the earlier studies. In our study, median lobe along with higher grade of lateral lobar enlargement was seen in 63.3%, 56.6% of patients with renal failure when compared to 33.3%, 36.6% in patients without renal failure. Mean operative time, amount of gland resected, drop in haemoglobin, need for blood transfusion and duration of hospital stay were comparable in patients with or without renal failure. Urinary flow rates are improved after the surgery and in the follow up period in all patients and postvoid residual volumes significantly decreased in all patients of BPH with renal failure.

Until now, no prospective and thorough assessment of the efficacy of TURP on renal function at short and long-term follow up has been available in the literature [13]. In referral based cohort studies; renal function appears to improve considerably with surgical treatment for prostate obstruction [11]. In our study, resolution of the renal failure was seen in 23 (76%) patients after initial catheterisation followed by TURP. In the remaining 7 patients, serum creatinine was abnormal but showed decreasing trend.

Men with large residual urine volumes with retention and concurrent UTI are at higher risk for renal failure. Upper tract dilatation, bladder wall thickening, poor compliance and detrusor overactivity can predict the presence or progression of renal failure in patients with BPH. Renal failure in the presence of comorbid illnesses, such as diabetes mellitus and hypertension, may be augmented by BPH. Renal function improves considerably after initial catheterisation followed by surgical treatment.