We examined symptom variabi
lity in men and women with uro
logica
l chronic pe
lvic pain syndrome. We describe symptom f
luctuations as re
lated to ear
ly symptom regression and its effect on estimated 1-year symptom change. We a
lso describe a method to quantify patient specific symptom variabi
lity.
Materials and Methods
Symptoms were assessed biweekly in 424 subjects with urological chronic pelvic pain syndrome during 1 year. To evaluate the impact of early symptom regression subjects were classified as improved, no change or worse according to the rate of change using 1) all data, 2) excluding week 0 and 3) excluding weeks 0 and 2. Patient specific, time varying variability was calculated at each interval using a sliding window approach. Patients were classified as high, medium or low variability at each time and ultimately as high or low variability overall based on the variability for the majority of contacts.
Results
Prior to excluding early weeks to adjust for early symptom regression 25% to 38% and 5% to 6% of patients were classified as improved and worse, respectively. After adjustment the percent of patients who were improved or worse ranged from 15% to 25% and 6% to 9%, respectively. High and low variability phenotypes were each identified in 25% to 30% of participants.
Conclusions
Patients with urological chronic pelvic pain syndrome show symptom variability. At study enrollment patients had worse symptoms on average, resulting in a regression effect that influenced the estimated proportion of those who were improved or worse. Prospective studies should include a run-in period to account for regression to the mean and other causes of early symptom regression. Further, symptom variability may be quantified and used to characterize longitudinal symptom profiles of urological chronic pelvic pain syndrome.
