Depression in COPD patients is one of the most common, yet least recognized comorbidities, with prevalence ranging from 17% to 44%.
Adherence is also low in nondepressed patients with COPD
New onset depression was a strong predictor of poor adherence to maintenance medications among a nationally representative sample of older patients with chronic obstructive pulmonary disease.
Average monthly adherence to COPD maintenance medications was low overall among the cohort of more than 30,000 Medicare beneficiaries, peaking at 57% in the month following first prescription fill after a COPD diagnosis and decreasing to 35% within 6 months.
Adjusted regression analysis linked depression to decreased adherence to COPD medications (odds ratio 0.93, 95% CI 0.89-0.98) in the study by researcher Jennifer Albrecht, PhD, of the University of Maryland School of Medicine, Baltimore, and colleagues published online June 24 in the journal Annals of the American Thoracic Society.
"Comorbid depression in COPD resulted in decreased adherence, as did the presence of any other comorbid condition, except asthma, suggesting that multimorbidity decreases adherence, possibly through complex medication regimens or patient prioritization of one comorbid illness over another," the researchers wrote.
Even though maintenance medications, including inhaled corticosteroids, long-acting Î²-agonists and long acting anticholinergics reduce exacerbations and improve lung function among COPD patients with moderate to severe disease, adherence to these medications remains low.
Depression is also a common comorbidity among patients with COPD, and it has been associated with poorer adherence to medications in patients with other chronic diseases, such as diabetes, said study co-author Linda Simoni-Wastila, PhD, of the University of Maryland in Baltimore.
"Depression can easily evade clinicians who are focused on FEVs or a broken hip, but it is a serious condition that can affect an individual's function, both physical and cognitive. Not to mention quality of life," she said in an email exchange with MedPage Today.
"Individuals with COPD have a risk of depression and it's imperative that clinicians consider this risk and treat and/or refer their patients for their emotional health in order to adequately manage COPD."
The newly published analysis included claims data on 31,033 Medicare beneficiaries diagnosed with COPD between 2006 and 2010 who filled at least two prescriptions for a COPD maintenance medication. Close to two-thirds of the sample (65.8%) were female and more than four-fifths (83.2%) were white.
During a 24-month follow up, roughly 20% of the sample received a diagnosis of depression.
"Depressed beneficiaries were more likely to be female (74.4% versus 62.4%, P<.001), to have more than three comorbid conditions (32.6% vs 22.6%, P<.001), and to have evidence of a nursing home stay (12.1% vs 4.8%, P<.001)," the researchers wrote.
Beneficiaries with depression had more severe COPD symptoms in the month of depression diagnosis as evidenced by higher rates of oxygen use (9.7% versus 8.2%, P<.001).
Among the cohort overall, adherence to COPD maintenance medications dropped dramatically within the first 6 months of use, but the patients with evidence of depression were less likely to remain adherent than patients without depression.
Just 22% of the overall cohort achieved adherence of 80% or more, even though the cohort included only patients with at least two medication fills over a 2-year period following COPD diagnosis. This suggests that even patients who are highly motivated to remain medication adherent have trouble doing so, the researchers noted.
"While our study findings suggest the first six months after COPD diagnosis is a critical time period for medication monitoring, given the chronic and progressive nature of COPD, close attention throughout the disease's trajectory may be important," the researchers wrote.
Patients with the highest risk for poor maintenance medication adherence were those with more than three chronic conditions, but this effect was mitigated by increased severity of COPD symptoms, evidence by acute inhaler oxygen use, and COPD-related hospitalizations.
Study limitations cited by the researchers included the reliance on Medicare claims data to identify depression in the cohort, given that depression tends to be underdiagnosed in administrative claims data.
The burden of depression may have also been underestimated, due to the exclusion of patients with dysthymic disorder and depression related to bipolar and schizoaffective disorder from the study.
The researchers concluded that prospective, longitudinal studies are needed to replicate their findings and to "further explore the relationship of these comorbid conditions."
Funding for this research was provided by the National Institutes of Health.
The researchers declared no relevant conflicts of interest.
Reviewed by Henry A. Solomon, MD, FACP, FACC Clinical Associate Professor, Weill Cornell Medical College and Dorothy Caputo, MA, BSN, RN, Nurse Planner
Source Reference: Albrecht JS., et al "Adherence to maintenance medications among older adults with chronic obstructive pulmonary disease: the role of depression" Ann of Am Thor Soc 2016; June 24: Online.
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