SUBJECTS AND METHODS
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- SUBJECTS AND METHODS
- CONFLICT OF INTEREST
The study was conducted in the rural community of Surahammar, Sweden, where, in 1997, the 11 200 inhabitants included 2571 men aged 40–80 years. All of the men invited to take part had participated a year earlier in a self-administered questionnaire study (‘yes’ or ‘no’) investigating the prevalence of three common LUTS, i.e. stress incontinence, urgency and post micturition dribbling . All 504 men who had reported one or more LUTS were invited to take part in the present study. As a control group, 504 randomly selected men from the same community who had reported no LUTS in the previous study were matched by age to the group that had reported LUTS, and they were also invited to participate (Fig. 1). These 1008 men were all sent a letter of invitation explaining the objectives of the study, and a postal reminder was sent twice to those who did not reply within 4 and 6 weeks.
Figure 1. Flow chart. Men with LUTS (post micturition dribbling, stress incontinence or urgency) who participated in a previous study  (indicated with 1) were investigated in the present study with the DAN-PSS questionnaire and three questions from the SF-36 (indicated with 2).
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The respondents completed a self-administered questionnaire, the Danish Prostatic Symptom Score (DAN-PSS , comprising 12 questions relating to LUTS), and three general questions about health, sadness and happiness, from the Swedish version of the Medical Outcomes Study Short-Form 36 health survey (SF-36) . Information was also collected about potential confounding and effect-modifying factors, e.g. social status, education, marital status, smoking, physical activity and UTI during the preceding year.
In the DAN-PSS, the severity or frequency of specific symptoms of LUTS were assessed on a four-category scale (no, mild, moderate, much). ‘Urge incontinence’, ‘stress incontinence’, ‘other’ incontinence, hesitancy, incomplete emptying, straining, dysuria and urgency were classed as ‘mild’ when the symptom was reported to occur rarely, ‘moderate’ when the symptom occurred often and ‘much’ when the symptom occurred always. ‘Weak stream’ was classed as ‘mild’ when the urinary stream was weak, ‘moderate’ when very weak, and ‘much’ when classified as dribbling. ‘Daytime frequency’ was classed as ‘mild’ when the interval between voids was 2–3 h, ‘moderate’ when 1–2 h, and ‘much’ when <1 h. ‘Nocturia’ was classed as ‘mild’ when it occurred once or twice at night, ‘moderate’ when three to four times, and ‘much’ when five or more times. ‘Post micturition dribbling was classed as ‘mild’ when dribbling was reported only to take place in the lavatory, ‘moderate’ when a small amount of dribbling occurred in the trousers, and ‘much’ when a large amount of dribbling occurred in the trousers.
The questions that were used from the general SF-36 questionnaire  related to self-assessed health, sadness and happiness (Appendix 1). Outcome variables for the self-assessed health, sadness and happiness questions were dichotomised. The response relating to the health question was classed as ‘low’ if the answer was ‘moderate’ or ‘bad’. Sadness was classed as ‘high’ if the answer was ‘all of the time’, ‘most of the time’‘some of the time’ or ‘part of the time’. Happiness was classed as ‘high’, if the answer was ‘all of the time’ or ‘most of the time’ (Appendix 1). For dichotomised symptom characteristics, the variables were classified as ‘no symptom’ or ‘symptom’. To calculate relative risks (RRs), the percentage of men reporting a specific symptom was divided by the percentage of men reporting no levels of the same symptom. The RRs for background characteristics were calculated as the percentage of men with LUTS reporting the outcome divided by the percentage of men with no LUTS who reported the same outcome. The RR and 95% CI were calculated and proportions used to describe the number and percentage of men with specific LUTS. The ethics committee at Uppsala University approved the study.
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- SUBJECTS AND METHODS
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The symptom burden from LUTS determines self-assessed health, sadness and happiness. Most LUTS that were measured in the present study by the DAN-PSS (12 symptoms) had a negative effect on these factors, and there was a strong correlation between the number of LUTS reported and self-assessed health and happiness. A significant difference was already apparent in men affected by one LUTS (RR 1.5), and the prevalence of a low score for health continued to increase with up to eight LUTS. The prevalence of a high score for happiness decreased and that of a high score for sadness increased in the same way, associated with increased LUTS burden. These data are supported by studies of self-assessed variables of well-being. Henningsohn et al. reported that the number of chronic symptoms after treatment for urinary bladder cancer determines the risk of a lower self-assessed well-being, while Koskimaki et al. reported that reduced health was associated with an increased LUTS impact, as measured using the DAN-PSS questionnaire. Correlations have also been found when the impact of LUTS was measured by other methods, e.g. the IPSS [11,12].
In the present study, symptom severity was associated with negative effects on self-assessed health, sadness and happiness. Other studies have also shown negative effects of increasing symptom severity on different QoL domains (SF-36 and King's Health Questionnaire) [4,6,13], thus it appears that the same effect can be measured by extracting key questions from the more extensive QoL questionnaires that are often used.
Different LUTS affect self-assessed health, sadness and happiness in different ways. ‘Other’ incontinence and urge incontinence appear to have a greater impact on health than stress incontinence. In another population-based Swedish study by Hägglund et al., urge incontinence had a greater effect on QoL than stress incontinence in women. It is reasonable to assume that unavoidable urge incontinence that appears suddenly is more distressing than an avoidable symptom such as stress incontinence. The avoidability of this symptom could be one explanation for the results of another study by our group , which shows that ‘high-severity’ stress incontinence causes moderate/much distress among a much higher proportion of affected men (67%) than in men with a ‘low-severity’ level of the symptom (21%). Thus, when it occurs, it causes high levels of distress, but because it is avoidable, the affected person avoids risky situations and thereby prevents negative effects on QoL.
Although ‘other’ incontinence was not the most prevalent LUTS, it had a considerable effect on self-assessed health, sadness and happiness. It is therefore important to assess not only highly prevalent LUTS but also symptoms with a low prevalence and which affect QoL in the clinical situation. The findings by Peters et al., that nocturia influences ‘everyday life’, supports the present finding that this symptom has negative effects on perceived health, sadness and happiness. ‘Weak stream’ was also significantly correlated with a lower level of self-assessed health and happiness, and to a higher level of sadness. This has also been discussed previously , and could reflect fear of prostate cancer.
The differences between men with LUTS and men with no LUTS with respect to social status, education, marital status, smoking, physical activity and UTI indicate that LUTS have a particular impact on self-assessed health and happiness. Koskimäki et al. found that the RR of a reduction in QoL after adjusting for age and different diseases was higher in men with LUTS than in with men with no LUTS. Unfortunately, in the present study, no specific questions were asked about other diseases.
LUTS were self-reported and the classification based on a questionnaire answered in the home environment. No clinical investigations were undertaken to validate the reported LUTS. The use of a questionnaire in the home environment probably results in fewer investigator errors than, for example, a personal interview [18,19]. As a result, the misclassifications that might have occurred using this method are difficult to assess objectively, but the risk should be low, as the DAN-PSS is a validated questionnaire designed for self-assessment . The Swedish population register provides information on all residents in the country, the present study is based on a large population, and we see no indications that men in this community differed from men in the rest of the country. It is always risky to generalize results from one study population to others, but the prevalence of LUTS is commonly described as being about the same in other countries of the world.
It is difficult to define when symptoms do not merely constitute a normal physical condition or behaviour; LUTS should be evaluated individually, together with the patient's discomfort level from the same symptom. In the present study, we included all LUTS, irrespective of discomfort level, and included the symptom if it was reported at any level in the DAN-PSS. For some LUTS the reported symptom level might represent a ‘normal’ condition, rather than a pathological condition for that individual. Counting these low-grade symptoms together with high-grade symptoms might dilute the results obtained. Self-assessments of LUTS have previously shown limitations; Malmsten et al. found that self-reported urinary incontinence could not be verified objectively in 4.6% of the participants. In the present study, self-assessed health, sadness and happiness were evaluated by three questions from a disease-independent questionnaire, the SF-36; we consider that the most reliable evaluation of LUTS, as well as quality factors, is the self-assessment of specific questions and not a summarized score from many different questions.
Bias could have been introduced during the selection of the study base (Fig. 1). The cohort in the present study consisted of 1008 men, i.e. 504 who 12 months earlier reported the occurrence of one or more of three LUTS , and 504 age-matched men from the same community. To minimize misrepresentation, two postal reminders were sent to those not responding, but more men who had reported LUTS answered the questionnaire than men with no earlier reported LUTS. Consequently, nothing indicates that the differences between men with LUTS and the controls are large enough to jeopardise the study results, but we cannot exclude the possibility that the 26% who did not respond biased the results. Even if the present results confirmed the need to assess QoL questions, most men with LUTS are still unknown to the healthcare system . Therefore, the aim of a future study would be to focus on the reasons for health-care seeking, which have been poorly documented and analysed.