Relationship of family caregivers' associated factors with medication adherence among elderly with tuberculosis in Iran.

Background And Objective: The global incidence rate of tuberculosis and related death among the elderly are 3 times and 6 times more than that of non-elderly, respectively. Therefore, the successful treatment of tuberculosis in the elderly affects all national tuberculosis control programs. Given the fact that "medication adherence" is the main key to effective treatment, it is essential to identify the factors related to medication adherence in the elderly with tuberculosis and provide appropriate interventions. Family caregivers play a pivot role in the elderly care and treatment, and their characteristics can influence the medication adherence of the elderly with tuberculosis. The objective of present study was determining the medication adherence of the elderly with tuberculosis and the factors related to their family caregivers in Iran.

Method: The present study was carried out through descriptive-analytical method and convenience sampling. 305 elderly patients with tuberculosis as well as their family caregivers who met the inclusion criteria were selected from those who referred to infectious diseases clinic of Masih Deneshvari Hospital in Tehran. Demographic and background data, 12-item standard general health questionnaire, Zarit Scale of Caregiver Burden questionnaire and Morisky Green Levine Medication Adherence questionnaire were used for the elderly with tuberculosis. The significance level for statistical tests was considered 0.05. Data analysis of the study was done using SPSS-25 software. Independent -test, One-way ANOVA, Tukey's test, Spearman's correlation test and ordinal logistic regression model were also used for the analytical statistics.

Findings: Out of the elderly with tuberculosis, 44.92 % had low medication adherence, 27.54 % had moderate medication adherence, and 27.54 % had full medication adherence. Medication adherence of married elderly was significantly better than single, widowed or lonely elderly (p < 0.001 and F = 53.192). The medication adherence was significantly better among the elderly whose caregivers had better general health (p > 0.001 and r = 0.776) and no burden or low burden according to Zarit scale (p > 0.001 and F = 357/96). In addition, there was a significant relationship between general characteristics of the caregivers (age, gender, marital status, number of children, education, knowledge about tuberculosis, sources of information, relativity to the patient, number of caregivers, employment status, and affordability) and the medication adherence of the elderly with tuberculosis. The results of simultaneous regression test of ordinal logistic regression showed that variables predict medication adherence behavior to a very acceptable level. The coefficient of determination values obtained from McFadden (0.4), Nagelkerke (0.747) and Cox-Snell (0.714) statistics demonstrated high explanatory power of the model by predictor variables.

Conclusion: The results of the present study suggested that the characteristics of family caregivers were associated with the medication adherence of the elderly patients. Therefore, policy making, providing treatment protocols emphasizing on the family role, investigating the characteristics of caregivers during patient visits and performing appropriate interventions will play vital roles in improving medication adherence of the elderly and controlling tuberculosis.