Health Care Contact Days for Older Adults Enrolled in Cancer Clinical Trials

Contact days-days with health care contact outside the home-are a measure of how much of a patient's life is consumed by health care. Clinical trials, with a more uniform patient mix and protocolized care, provide a unique opportunity to assess whether burdens differ by individuals' sociodemographic backgrounds.

To characterize patterns of contact days for older adults with cancer participating in clinical trials.

In this cohort study, data from 6 SWOG Cancer Research Network trials across prostate, lung, and pancreatic cancers that recruited patients aged 65 years or older from 1999 to 2014 were linked with Medicare claims data. Data were analyzed from December 14, 2023, to September 26, 2024.

Demographic variables, including age, sex, self-reported race and ethnicity, and insurance status; clinical factors, such as cancer type and study-specific prognostic risk score; and social factors, such as neighborhood socioeconomic deprivation.

Number of contact days, defined as number of days with contact with the health care system, percentage of health care contact days (number of contact days divided by follow-up), and sources of contact days (eg, ambulatory or inpatient) in the first 12 months after trial enrollment. Sociodemographic and clinical factors associated with contact days were examined using negative binomial regression, including an offset variable for duration of observation.

The study included 1429 patients (median age, 71 years [range, 65-91 years]; 1123 men [78.6%]; and 332 patients [23.5%] with rural residence). The median number of contact days was 48 (IQR, 26-71), of a median of 350 days (IQR, 178-365 days) of observation; the median percentage of contact days was 19% (IQR, 13%-29%). The most common sources of contact days were ambulatory clinician visits (median, 17 [IQR, 7-25]), tests (median, 12 [IQR, 3-24]), and treatments (median, 11 [IQR, 3-22]). A median of 70% (IQR, 50%-88%) of ambulatory contact days had only a single service performed on that day (eg, only tests). In multivariable regression, factors associated with increased contact days included age (relative risk [RR] per year, 1.02 [95% CI, 1.01-1.02]), insurance type (Medicare alone or with Medicaid or private insurance vs other: RR, 2.47 [95% CI, 2.16-2.83]), prognostic risk score (above the median vs at or below the median: RR, 1.14 [95% CI, 1.04-1.25]), and type of cancer (pancreatic vs prostate cancer: RR, 1.69 [95% CI, 1.51-1.89]; lung vs prostate cancer: RR, 1.69 [95% CI, 1.54-1.85]).

In this cohort study of older adults with advanced stage cancer participating in phase 3 randomized clinical trials, patients spent nearly 1 in 5 days with health care contact. These findings highlight the need to simplify trial requirements to minimize participant burden.