Is there a relationship between self-reported healthy days and comorbidity medication adherence among oncology patients?

189 Background: Previous studies established the link between comorbidities and Health Related Quality of Life (HRQoL) for cancer patients. Adherence to comorbid medications has been found to be predictive of HRQoL in other disease states, but this has not been established for patients with cancer. This study sought to investigate the association between healthy days (HDs) and comorbidity medication adherence (CMA) for cancer patients.

METHODS: A survey was mailed to 5,098 patients with metastatic breast, lung or colorectal cancer who received treatment in 2014 and had at least one comorbid condition. Survey responses were merged with Humana claims data for analysis. The CDC's Healthy Days measure was used to identify self-reported overall, physical and mental unhealthy days in the past 30 days and the number of days that poor physical or mental health limited usual activities. The Morisky Medication Adherence 8-point scale was used to differentiate high CMA ( > 6) and low CMA ( < 6). P-values are from chi-square and t-tests.

RESULTS: The survey response rate was 32% (N = 1,629). Respondents were mostly female (66%), and Medicare beneficiaries (90%) with mean age of 69.7 years. Patients with lung cancer experienced more overall unhealthy days than those with either breast or colorectal cancer (mean: 16.2 vs 12.6 and 13.5, p < 0.0001). The number of overall unhealthy days was higher among patients with low CMA compared to high CMA (mean: 15.4 vs 13.5, p = < 0.0001). Patients with low CMA had more mentally unhealthy days than those with high CMA (mean: 6.0 vs 8.2, p = 0.0128). There was no difference in physically unhealthy days by CMA. Patients with low CMA had 3.7 more unhealthy days that kept them from doing their usual activities (12.0 vs 8.3, p< 0.0001).

CONCLUSIONS: Surveyed oncology patients with high comorbidity medication adherence reported fewer unhealthy days, in particular mentally unhealthy days, in the past 30 days. The complex interplay between comorbidity medication adherence and HDs for cancer patients warrants further investigation. These results suggest that increasing patients' level of comorbidity medication adherence may be an avenue for improving the number of healthy days they experience.