Hypothesis / aims of study
Symptoms of urologic chronic pelvic pain syndrome (UCPPS, including interstitial cystitis/bladder pain syndrome and chronic prostatitis/chronic pelvic pain syndrome) are well-known to fluctuate, with symptom exacerbations – periods of time when symptoms are much worse than usual – often referred to as “flares.” Previous studies have shown that flares are associated with decreased quality of life (QOL) and greater health-care utilization, with the degree of impact driven by the frequency, pain intensity, duration, and unpredictability of flares.
Despite their negative impact on patients’ lives, flares are rarely documented in UCPPS research. Most UCPPS studies monitor changes in participants’ condition by assessing changes in their typical or average levels of pain and urinary symptoms or their impression of changes in their condition over time (i.e., global response assessment). Both of these measures have been shown to correlate with QOL and illness impact, supporting their use as outcomes in UCPPS research. Although flares have also been shown to impact QOL, no studies, to our knowledge, have investigated whether flares influence QOL, health-care seeking behavior, and illness impact independently of typical pain intensity, and thus whether they merit consideration as additional outcomes in UCPPS research (i.e., whether reducing flare frequency without reducing mean pain intensity may still be important to patients). Therefore, we used data from the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Symptom Patterns Study to investigate associations between flares and QOL, health-care seeking activity, and illness impact, independent of mean pain levels. We hypothesized that flares would be associated with QOL, health-care seeking activity, and illness impact, independent of typical pain intensity, and that this impact would be greatest for patients with the highest flare frequency.
Study design, materials and methods
The MAPP Symptom Patterns Study was a three-year longitudinal study of UCPPS patients designed to investigate the “usual-care” natural history of UCPPS and to identify patient sub-groups with possible differing etiology and clinical course. Initial study participation involved attending a “screening” visit (week 0); completing three weekly, online “run-in” assessments (weeks 1, 2, and 3); and then attending a “baseline” study visit at week 4. After the baseline visit, participants were followed by quarterly online assessments and in-person visits at 6, 18, and 36 months of follow-up. Recruitment began in July 2015 and ended in February 2019.
At the screening visit and each run-in assessment, participants were asked to report their frequency of flares and typical pelvic pain levels; as well as to provide information on condition-specific QOL (Genitourinary Pain Index Quality of Life Impact Sub-Scale), condition-specific health-care seeking activity (MAPP-specific item), and general illness impact or disability (World Health Organization Disability Assessment Schedule). Standardized beta coefficients were calculated by generalized estimating equations and used to estimate associations between flare frequency and QOL, health-care seeking activity, and illness impact, independent of typical pelvic pain levels (Figure 1).
Results
Overall, 592 of 620 Symptom Patterns Study participants were eligible for the analysis. In minimally-adjusted models, participants who reported at least 1 flare/week had worse condition-specific QOL, and those who reported at least 2 flares/week had greater health-care seeking activity and general disability than those who reported no flares in the past week. After adjustment for typical pelvic pain intensity, associations attenuated, but remained statistically significant for at least one flare/week with worse condition-specific QOL, at least 2 flares/week with greater health-care seeking activity, and at least 1 flare/day with worse overall disability (Table 1 and Figure 1).
Interpretation of results
Our findings suggest that patients who experience flares have worse QOL and greater health-care seeking activity and illness impact than patients who do not experience flares, independent of typical pelvic pain levels. Our findings also suggest greater impact with increasing frequency of flares.
Concluding message
Our observation of independent associations between flares and QOL, health-care seeking behavior, and illness impact suggest that patients may benefit from treatment and management strategies that reduce their flare frequency, even if they do not reduce their overall pain intensity. For this reason, we propose that flares are worth considering as additional outcomes in clinical trials and other research studies, as well in clinical practice.