Adherence to treatment is essential in chronic diseases, especially in chronic obstructive lung diseases (COLD). Poor adherence to the treatment regimen and improper use of inhaler devices lead to adverse clinical outcomes and an unnecessary use of healthcare resources.1 In a recently published study, Japanese researchers showed that the adherence rate to inhaled medicines was lower than for oral medicines in patients with COLD, suggesting patients experienced problems using the devices.2 Nonadherence to the treatment regimen and inadequate inhaler technique are important causes of therapy failure, especially in elderly patients. A study showed the overall prevalence of using inhalers correctly was 31% and no improvement was observed over time.3 For these reasons, we evaluated adherence rates of our patients, including whether they used inhaler devices properly and the underlying reasons if they did not.
MATERIALS AND METHODS
Patients ≥65 years old were classified as elderly, while patients <65 years of age were classified as non-elderly. A questionnaire was answered by patients with COLD within a scheduled time period. Cognitive functions of the patients were evaluated by the Mini-Mental State Examination (MMSE) and disease control status was assessed using an appropriate disease-specific questionnaire. The adherence to inhaled therapy and inhaler device use were evaluated by the Test of Adherence to Inhaler Treatment (TAI) questionnaire. The first 10 components of the TAI are designed to identify nonadherent patients, while the last two items identify compliance with treatment regimen and proper device use.
The study recruited 135 patients (69 asthmatics and 66 chronic obstructive pulmonary disease [COPD] patients). The elderly group consisted of 54 patients and the non-elderly group was composed of 81 patients; the groups had a similar sex distribution. The proportion of patients with COPD was higher than those with asthma in the elderly group. Dry powder inhalers were the most commonly used device among COLD patients for chronic therapy (40.0%), while the second most common was separated capsules (22.2%). MMSE score was lower in the elderly group than in the non-elderly group (27 versus 28; p=0.022), but the rate of cognitive impairment was similar between the groups. Adherence level according to TAI-10 was 25.9% and overall disease control rate was 35.4% in the whole study group. The adherence scores according to TAI-10 were higher in the elderly group than in the non-elderly group (median: 49 versus 47; p=0.004) and there was also a higher adherence rate in the elderly group (37.0% versus 18.5%; p=0.016). Each component of the TAI was higher in COPD patients than in asthmatics and the differences were statistically significant. In addition, unconscious noncompliance rate was higher in the elderly than in the non-elderly according to items 11 and 12 (70.4% versus 55.6%; p=0.083). Seventy patients (51.9%) made critical errors when using inhaler devices and the elderly group and COPD patients made more critical errors (p=0.005 and p=0.020, respectively). No difference was found in critical errors according to the type of inhaler device. Logistic regression analysis showed that age and being informed about the disease were associated with critical errors. For example, being ≥65 years old increased the risk by 2.536-fold and not being informed about the disease increased the risk by 2.254-fold (p=0.015 and p=0.029, respectively).
Adherence to inhaled drugs is lower than that of other treatment methods in chronic diseases. The reasons for this may include both the requirement for compliance with the treatment regimen and the proper use of inhaler devices. In this study, a high critical error rate was found in elderly patients, especially those with COPD, independent of the type of inhaler device.