The natural history of lower urinary tract dysfunction in men: the influence of detrusor underactivity on the outcome after transurethral resection of the prostate with a minimum 10-year urodynamic follow-up
Bristol Urological Institute, Southmead Hospital, Bristol, UK
In the first paper in this section the authors from the Bristol Urological Institute investigated 224 men with detrusor underactivity, and evaluated the effect of this condition on the outcome of TURP. This quite unique study found that TURP is not helpful in this condition. They underscored their view that reliance on symptoms and uroflowmetry is not enough when patients are being considered for TURP, and recommended routine preoperative urodynamic assessment.
There is an updated meta-analysis of clinical trials of Permixon in the treatment of symptomatic BPH presented in this section. The authors review all clinical trial data from 14 randomized and 3 open-label trials. Although the trials varied widely in methods the meta-analysis showed a significant improvement in symptoms and flow rates in patients treated with this compound.
Authors from Leicester assessed the prevalence and incidence rates for urinary incontinence and storage disorder in the UK over a 1-year period, finding that this constituted a major public health problem, with consequent effects on services and funding.
To assess the long-term outcome of the efficacy of transurethral resection of the prostate (TURP) in men with detrusor underactivity (DUA), a cause of lower urinary tract symptoms (LUTS) in a significant minority of men.
PATIENTS AND METHODS
Neurologically intact men with LUTS, who were investigated in our department between 1972 and 1986, diagnosed with DUA and who underwent surgical intervention, were invited for a repeat symptomatic and urodynamic assessment. Identical methods were used, allowing direct comparison of the results.
In all, 224 men were initially diagnosed with DUA; 87 (39%) of these died in the interim and 22 followed had a TURP, with a mean follow-up since surgery of 11.3 years. There were no significantly sustained reductions in any symptoms. There was a small but significant reduction of questionable clinical significance in the bladder outlet obstruction index, but this did not translate into an improved flow rate. Comparison with 58 age-matched patients with DUA who remained untreated showed no significant advantage of surgical intervention in the long-term; on the contrary, there was more chronic retention in those who had had surgery.
There are no long-term symptomatic or urodynamic gains from TURP in men shown to have DUA. The results of TURP in men with DUA are important, as urologists who surgically treat patients based on the symptoms and uroflowmetry alone will do so in a significant minority of men with DUA. These results strengthen the argument for a routine preoperative urodynamic assessment.
Detrusor underactivity (DUA) in men is responsible for LUTS in a significant minority , the symptoms being indistinguishable from those seen in BOO. The International Continence Society (ICS) defines DUA as ‘a detrusor contraction of inadequate magnitude and/or duration to effect complete bladder emptying in the absence of urethral obstruction’. Whilst a reduced maximum urinary flow rate (Qmax) is indicative of voiding dysfunction, flow studies cannot distinguish between DUA and BOO, which are the two principal causes of low flow rates. DUA is diagnosed from a pressure-flow study (PFS) and is characterized by a low-pressure, poorly sustained, or wave-like detrusor contraction with an associated poor flow rate.
There are virtually no data evaluating the efficacy of TURP in men with DUA, although men with lower voiding pressures have been shown to have a worse symptomatic outcome after elective TURP . An operation designed to relieve BOO, where detrusor failure is the underlying pathology, would seem unlikely to produce any improvement in voiding efficiency. However, it has been mooted that a reduction in outlet resistance may produce more efficient emptying by straining. In the present study we aimed to assess primarily the long-term urodynamic outcome, and secondarily the associated changes in symptoms, of men who had a TURP for DUA.
PATIENTS AND METHODS
The Bristol Urological Institute is probably unique in that it has had a well-established urodynamic unit for the past 30 years, during which time urodynamic and symptomatic information on all patients has been kept. As well as a review of the urodynamic notes, the hospital notes were assessed to determine the timing and type of treatment interventions after the initial urodynamic investigation.
Neurologically intact men aged > 18 years at presentation, with a diagnosis of DUA and seen originally between 1972 and 1986, were traced and invited to the department for a repeat assessment. The definition of DUA used here was a detrusor pressure at Qmax (pdetQmax) of < 40 cmH2O, with a Qmax of < 15 mL/s, a definition similar to that of the ‘poor contractility zone’ of the recently described bladder contractility index (BCI) nomogram .
Mortality data were obtained from the UK Government Office for Population and Census Studies, and by an extensive search of the hospital records. Death certificates were obtained, providing the cause of death.
Patients were traced using the original urodynamic records, hospital records, telephone directory/directory enquiry searches, and by liaison with Community Family Practitioners, The Family Health Services Association and the National Health Service patient tracing service.
The same original physician-completed symptom proforma, in use from 1972 to 1986, was completed to assess the patient's current symptoms. Patients were also asked to complete a 7-day frequency-volume chart before their clinic appointment. The format of this chart has remained unchanged since 1972, and all patients had completed it as part of their original assessment, so allowing direct comparison. Patients also completed the IPSS questionnaire at the follow-up.
For the urodynamic assessments, at uroflowmetry the flows were expressed to the nearest 1 mL/s. The postvoid residual urine volume (PVR) was estimated after each flow test using ultrasonography.
For the PFS, standard methods and urethral pressure profilometry (Brown-Wickham technique) were used, applying techniques that remained unchanged since 1972, so allowing direct comparison of the results. Machine calibration, reference levels, quality control and trace interpretation were according to the recommendations of the ICS . All the original traces were available for inspection and therefore new methods of urodynamic analysis were applied retrospectively. Pressures were expressed to the nearest 1 cmH2O. All patients had a MSU specimen sent for microbiological analysis, to exclude infection.
Detrusor function was assessed using two variables; the BCI was calculated as pdetQmax+ 5Qmax, and the bladder voiding efficiency (BVE) as (voided volume/cystometric capacity), expressed as a percentage . The degree of obstruction was represented by the Abrams-Griffiths number  or the BOO index (BOOI) , both calculated as pdetQmax − 2Qmax.
The hospital records of patients who were followed and referred to our unit were searched for interventional details after presentation, which included information before, during and after TURP.
The paired Student's t-test was used to compare the results at presentation and follow-up for normally distributed data, with Wilcoxon's signed-ranks test for skewed data. The two-sample (unpaired) t-test was used to compare normally distributed data at presentation between different groups, with the Mann–Whitney test for skewed data. The chi-squared test (with Yates correction where appropriate) was used for the remainder of the analyses. Two-tailed statistical significance was judged at the 5% level.
Figure 1 summarizes the patient demographics of the study population; 2066 men were referred for an assessment of their LUTS and had PFS, urodynamic, uroflowmetry and symptom evaluation between 1972 and 1986. There were 224 neurologically normal men aged > 18 years with a diagnosis of DUA, of whom 137 (61%) were still alive at the time of the follow-up study. Of those still alive, 84 (61%) were re-assessed; 64 (76%) with a full re-evaluation, six (7%) with uroflowmetry and for symptoms, and 14 (17%) with a symptomatic appraisal only. Eleven of the men followed up (13%) had a primary TURP after their original PFS assessment, 69 (82%) adopted a conservative watchful-waiting policy, with four (5%) using clean intermittent self-catheterization (CISC) for significant chronic retention. Of those managed conservatively from the outset, 11 (16%) re-presented, three with acute urinary retention and eight with worsening LUTS, all subsequently undergoing TURP. Of those managed conservatively, 58 (84%) remained untreated.
Table 1 summarizes the symptomatic and urodynamic findings in those men who had a TURP. Symptomatically there was no significant change in the number of daytime or night-time voids, or the proportions of patients describing individual storage or voiding symptoms. There was a small but significant long-term reduction in the degree of obstruction, indicated by a reduction in the pdetQmax and hence the BOOI. However, there was no change in Qmax, with contractility also remaining unchanged. Of the six patients on long-term CISC for chronic retention there was no change in bladder function on PFS (data not shown).
Table 1. The data at presentation and the follow-up for 22 men with LUTS, aged > 18 years at presentation, with a diagnosis of DUA and who had a TURP
MUCP, maximum urethral closure pressure; *statistically significant.
Patients with DUA who remained untreated were statistically comparable at presentation with those who subsequently had a TURP (data not shown). There were no significant urodynamic or symptomatic differences between the groups, implying that factors other than those measured were involved in the decision to proceed to surgery. In view of this it is not unreasonable to compare their long-term follow-up data, to contrast the outcomes of these two methods of management; this is summarized in Table 2. There was a reduction in voiding pressure and obstruction in those who had a TURP compared with the untreated group. Also, those who had TURP had a small but significant reduction in detrusor contractility with time, which was associated with a greater degree of chronic retention of urine. The BVE was also significantly lower in the TURP group, providing evidence that those with DUA and who had a TURP have a poorer long-term urodynamic outcome than those who remain untreated. However, this was not translated into a difference in symptoms, corroborated by the identical IPSS and QoL in the two groups.
Table 2. Comparison of follow-up data of untreated vs treated men (TURP) in all patients with DUA who were followed up
MUCP, maximum urethral closure pressure; *statistically significant.
Of the original group of men in the database with DUA 87 (38.8%) had died since their initial assessment. An evaluation of the causes of death from death-certificate data showed no significant increase in mortality related to any urinary tract pathology. Of the 137 still alive, 53 (39%) have not been followed up; eight of these (15%) refused to participate, 26 (49%) were traced but did not reply to the invitation and 19 (36%) proved untraceable. The data at presentation of all those who were seen for the follow-up was compared with those who were not seen again, to test the hypothesis that those followed were representative of the whole database. Those not seen again were older at presentation. Although urodynamically there was no difference between the groups there were some symptomatic differences; a higher proportion of those not followed complained principally of storage symptoms, i.e. nocturia, urgency and urge incontinence, consistent with them being older. Stratifying the group who were not followed in an attempt to identify any volunteer bias, by first excluding those who had died and second those who were untraceable, resulted in less marked symptomatic differences from the investigated group. Overall, the follow-up group was less symptomatic at presentation.
Significant symptoms caused by lower urinary tract dysfunction in men are common. The symptoms not only affect the individual's health and quality of life, but also place a burden on the family, and on health and social services. As the population ages, especially with the ever-increasing life-expectancy, it is clear that the number of patients with LUTS seen by GPs, urologists, continence advisors and other healthcare professionals is likely to increase. The increase in the number of consultant urologists in the UK, in part, reflects the escalating demand for appropriate patient management.
The incidence of LUTS clearly increases with age [6,7]. The significant healthcare problems this poses are emphasized by estimates that more than half of men aged ≥ 50 years have LUTS . It is obvious that a full understanding of the disease processes and their treatments are required so that an economic and effective treatment protocol can be developed, and so that an informed discussion can take place between the physician and the patient.
The ICS definition of DUA  is limited to the voiding phase; characteristically this leads to a low urinary flow rate with or with no PVR. DUA cannot be differentiated from BOO with certainty, either from the symptoms or from the flow trace; they are indistinguishable from those of obstruction and thus DUA is diagnosed from PFS. However, an irregular flow with a Qmax in the latter half of the trace is suggestive of DUA.
There are few data evaluating the efficacy of TURP in those with DUA, although men with lower voiding pressures have a less favourable symptomatic outcome after elective TURP . This is important, as most men in the UK have a TURP for LUTS on the basis of symptoms and uroflowmetry only, and it is well recognized that DUA and BOO are indistinguishable on these two assessments. An operation designed to relieve BOO where detrusor failure is the underlying pathology would seem unlikely to produce any changes in voiding efficiency. However, we show here that there is minimal urodynamic change in a long-term follow-up of patients with DUA after TURP. There was a small long-term reduction in BOO, brought about by a reduction in voiding pressure with no significant change in flow rate. None of this was associated with a change in detrusor contractility. There were neither objective nor subjective changes in symptoms. We also provide evidence that those who have a TURP for DUA have a poorer urodynamic outcome than their age-matched counterparts managed conservatively, in that they had a higher PVR and lower BVE. However, this was not translated into a poorer symptomatic outcome; neither group were symptomatically changed.
A very few patients (six) were using CISC for chronic retention; four had this initiated immediately after their original PFS assessment, with two having an initial TURP, followed by CISC for ongoing chronic retention problems. On the long-term follow-up there was no apparent urodynamic benefit in these patients. From these results it seems that despite CISC maintaining bladder emptying, so minimizing the attendant complications of chronic retention, it produced no long-term improvement in voiding function. However, these results need to be interpreted with caution as there were so few patients.
This was a retrospective study and therefore has several shortcomings, particularly being prone to several selection biases. Within the British healthcare system there are relatively few urologists compared with the USA (1 per 100 000 vs 1 per 25 000 population, respectively). Hence most men with LUTS in the UK are managed in the community by GPs. The present patients were a selected group, consisting of those men who had significantly severe LUTS to want to consult their GP initially, and which warranted referral to a specialist urology clinic, but also required a precise urodynamic diagnosis. With the present study design we could not control for this, but it is likely to have made the results worse than might be expected in the general population. Following an insufficient proportion of the original patient cohort can also introduce bias. We followed 61% of those alive over 14 years after presentation. In an attempt to identify whether or not the follow-up group was self-selected we compared the data at presentation for all patients re-assessed against those who were not. The former group was younger, but they were urodynamically comparable, lending weight to the hypothesis that we were following a representative sample of the entire database. Also, in this study with a long follow-up of an elderly population, many patients died. Stratifying those not re-assessed into ‘alive’ and ‘dead’ yielded the same comparative result with the follow-up group as described above. However, as in all such studies, extrapolating these data to the community must be done cautiously.
The results on the outcome of TURP in patients with DUA are important. Surgery, for the most part, is usually used on the basis of LUTS suggestive of BOO, combined with results from uroflowmetry. DUA is indistinguishable from BOO on the basis of these criteria, and therefore urologists are operating on a significant minority of patients who are unobstructed. The present results show that after TURP for DUA, despite a clinically irrelevant reduction in BOO, there are no long-term urodynamic or symptomatic gains in this group, compared with the improvements shown in patients with BOO. CISC for chronic retention secondary to detrusor failure, despite minimizing the attendant complications of this disorder, produced no long-term change in voiding function. These results suggest that DUA is a contraindication for TURP and that DUA should be distinguished from BOO before surgery; this requires PFS.