Measuring Quality of Life in Patients with Gout

The prevalence of gout in the United States continues to rise, with some estimates indicating that as many as 9 million adults suffer from the condition—close to 4% of the population. Quality of life for patients suffering from gout can be dismal, and patients with gout will generally need some form of urate-lowering therapy (ULT) on a long-term basis, according to American College of Rheumatology and European League Against Rheumatism guidelines.

But will they stay on those medications? Despite the availability of effective and tolerable therapies, many gout patients do not achieve target serum urate levels, in part due to poor adherence to therapy. Studies have shown that patient satisfaction with treatment directly impacts whether or not they choose to adhere to their medication therapy.

A recent study in Patient Preference and Adherence looked at patient satisfaction with treatment via a mail survey to a managed care population. (The study authors all have connections to Takeda pharmaceuticals, manufacturers of febuxostat, one of the leading ULTs.) Eligible patients were over the age of 18 with self-reported gout who filled more than one prescription for febuxostat and were not taking other ULTs. Patients were stratified by self-report of currently experiencing a gout attack or not to assess the discriminant ability of the questionnaires.

The survey included the Treatment Satisfaction Questionnaire for Medication (TSQM) and gout-specific health-related quality of life (HRQoL) with the Gout Impact Scale (GIS). While the TSQM has been used in studies of other rheumatic diseases, the study authors believe this is the first time it has been used to evaluate treatment satisfaction among gout patients.

The final analytic sample included 257 patients who were taking only febuxostat when they completed the survey.Treatment satisfaction was assessed by the TSQM version II. Patients were asked on the TSQM to rate their level of satisfaction with the ULT they were currently taking for gout. The TSQM has 11 items, scored from 0 to 100, with higher scores indicating better satisfaction.

Patients with current gout attack (n=29, 11%) had worse scores than those without gout attack on most instrument scales. Mean differences between current attack and no current attack for the TSQM domains were: -20.6, effectiveness; -10.6, side effects; -12.1, global satisfaction (all P<.05); and -6.1, convenience. For the GIS, mean differences were: 30.5, gout overall concern; 14.6, gout medication side effects; 22.7, unmet gout treatment needs; 11.5, gout concern during attack (all P<.05); and 7.9, well-being during attack (NS). Correlations between several TSQM and GIS scales were moderate.

According to the study authors, “There were several moderate correlations between the TSQM and GIS scales, supporting the relationship between treatment satisfaction and HRQoL. The moderate correlations between the GIS unmet gout treatment needs and TSQM global satisfaction (-0.50) and effectiveness (-0.40) scales suggest that both measures captured the degree to which patients believed that their medication was beneficial for their gout treatment. The correlation between the side effect scales of the GIS and TSQM was also moderate (-0.46), indicating consistent findings from both instruments.”

Limitations of the study include the fact that almost all patients were taking febuxostat for at least 60 days, which may bias the results in favor of patients satisfied with treatment. The study also lacked a formal comparator group of patients taking a ULT other than febuxostat.