Background adherence to urate-lowering treatment (ULT) in patients with gout is reported to be lower than 50% in the first year, below 20% at 2-year, and worse than in other chronic conditions such as hypertension, diabetes, or hyperlipidemia.
Objectives to evaluate adherence to ULT both overall and during follow-up, to compare it to the adherence to medications for associated comorbidities, and to explore potential causes for non-adherence to ULT.
Methods transversal study of a nested cohort of patients in a gout clinic in the hospital setting who were scheduled for a follow-up visit during 6 consecutive months in 2016. General data of patients, along with variables related to gout and to comorbid conditions are systematically retrieved at first visit; prescribed ULT, doses, adherence, and serum urate levels were obtained during the follow-up visits. Adherence was retrieved as medication possession rate (MPR) according to pharmacy offices from government electronic databases (including >98% of the general population). Also, MPRs of drugs prescribed for hypertension, diabetes (only oral), and hyperlipidemia were obtained; if more than one drug prescribed for any of the previous, the best adherence per comorbidity treatment was entered. Good adherence was considered as MPR>80 percent of that prescribed, target serum urate (sUA) as <0.36 mmol/L. Patients are educated at first visit and encouraged to be adherent from baseline through follow-up visits.
Results adherence data were available from 209 patients who were scheduled for a follow-up visit during the observation period; 14 (6.7%) patients did not atend the visit. This sample was formed by 90% male, only 55% had received ULT previous to first visit, median age was 65 years at follow-up visit, 47% and 44% showed poliarticular and tophaceous disease at baseline, respectively. MPR overall showed a median of 89% (IQR 79–94, N=209) for ULT (72% had MPR>80), and 89% (IQR 81–94, N=119), 88% (IQR 79–94, N=65), and 82% (IQR 77–93, N=28) for hypertension, hyperlipidemia, and diabetes respectively (p<0.05 only for diabetes).
Adherence was lower for patients who did not attend the scheduled visit (median MPR 58% vs. 86%, MPR >80, 21% vs. 75%, p<0.01). Adherence was lower during the first year (80%, N=67) compared to 2nd and 3rd year period (86%, N=67) or 4 year or over (89%, N=75). MPR>80 was 57%, 76% y 81% for the same periods of follow-up, respectively. Good adherence was associated to a rate of target serum urate of 90%, compared to 72% for patients showing MPR<80.
Male gender and un-attendance to scheduled visit were statistically associated to MPR<80 in multivariate analysis, and numerically to increasing age and overall comorbidity.
Conclusions adherence to ULT measured as MPRs in a cohort of educated patients is good, sustained during follow-up, and similarly good to that for comorbid conditions (hypertension, hyperlipidemia, and diabetes); therefore, we cannot blame poor adherence on the patients anymore. Targeting absenteeism could be an opportunity for further improvement.
Disclosure of Interest F. Perez-Ruiz Consultant for: Amgen, Ardea, AstraZeneca, Gruenenthal, Menarini, Speakers bureau: AstraZeneca, Gruenenthal, Menarini, I. Urionagüena: None declared, S. Chinchilla: None declared