LONDON – Many patients with newly diagnosed gout who are prescribed allopurinol to reduce their uric acid level and prevent recurrent episodes fail to stick with their treatment, according to an analysis of more than 47,000 U.K. gout patients who received prescriptions for allopurinol during the 28-year period of 1987-2014.
One possible contributing factor to this pattern may be physicians who inadequately stress to patients the importance of sticking with allopurinol treatment to improve their long-term health, Lieke E.J.M. Scheepers said at the European Congress of Rheumatology.
“We think that physicians underestimate” the low level of gout patient adherence to allopurinol, said Ms. Scheepers, a PhD student in the department of rheumatology at Maastricht (the Netherlands) University.
“We view gout as a chronic disease, but many physicians and patients believe gout can occur as a single episode, and then it’s over,” explained Dr. Annelies Boonen, the senior investigator on the study, in an interview. “Gout patients often don’t appreciate that they will need to take their medication for many years. We need to convince primary care physicians to follow gout patients closely and not wait [to resume treatment] until the patient has a new episode,” said Dr. Boonen, a professor of rheumatology at Maastricht University.
“Some physicians are not convinced that it harms a patient to have two or three acute gout attacks a year, but there is a subgroup that will have joint damage” from this pattern of recurrence, she noted. However, Dr. Boonen acknowledged that gout patients usually seen in primary care practice often don’t have the same level of disease severity and recurrence as the patients she sees in her referral clinic. “We don’t know which gout patients will develop joint damage,” she admitted.
Another barrier to good adherence with long-term uric acid–lowering treatment is that “patients who don’t have daily symptoms often question why they should continue to take their medication,” added Ms. Scheepers. “Many patients fear the possible adverse effects of their treatment” more than they fear a possible gout recurrence.
Ms. Scheepers and her associates analyzed data from 47,774 patients with newly diagnosed gout receiving treatment exclusively with allopurinol from about 680 primary care U.K. physicians and archived in the Clinical Practice Research Datalink maintained by the U.K. government. The patients averaged 64 years old, and three-quarters were men.
During their first year on treatment, 57% of the patients had at least one 30-day gap in their use of allopurinol, and 38% had at least one 90-day gap in their allopurinol treatment, Ms. Scheepers reported. During an average follow-up of nearly 6 years, 77% of patients had at least one 30-day gap in treatment and 54% had at least one 90-day gap. The median time to a 90-day gap in allopurinol treatment was just under 3 years (1,059 days).
The researchers also assessed patient compliance and adherence to therapy by analyzing the percentage of days during follow-up that they took allopurinol. The overall average percentage of days on treatment was 57%, and 39% of patients received allopurinol on at least 80% of the days when they were followed.
Another analysis focused specifically on 14,808 patients who restarted on allopurinol after they had stopped their use of the drug for at least 90 days. Among these patients, the rate of a new 30-day gap during their first year back on treatment was 72%, with 48% having a new gap of 90 days or more during their first year back on treatment. During total follow-up of this group of patients with an established history of stopping allopurinol, 82% had a new gap in treatment of at least 30 days and 63% had a gap of 90 days or more.
The researchers also examined demographic and clinical variables that significantly linked with either greater or lesser adherence to allopurinol treatment. Two subgroups – women and smokers – showed significantly worse adherence, while older patients, patients who also took other drugs (antihypertensive medications, colchicine, or statins), and patients with various comorbidities (dementia, diabetes, depression, or impaired renal function) all had significantly better adherence. One possible explanation for this pattern is that patients who are older, have comorbidities, or already take other drugs may have a better-established routine and mindset for adhering to medication regimens that helps them remain adherent to allopurinol, Ms. Scheepers said.
Dr. Scheepers and Dr. Boonen had no disclosures.
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