Diagnosis of advanced cancer among elderly Medicare and Medicaid patients

Medicaid is implicated in late-stage cancer diagnoses, which is the primary indicator of a poor prognosis.

We examined Medicaid enrollment and cancer diagnosis in patients ages 66 years and older. Medicaid enrollment was defined as enrolled 12+ months before diagnosis, enrolled <12 months before diagnosis, and enrolled after diagnosis.

Medicaid and Medicare administrative data were merged with the Michigan Tumor Registry to extract a sample of 46,109 patients with a first primary diagnosis of prostate, lung, breast, or colorectal cancer between 1997 and 2000. Measures were: (1) diagnosed during the same month as death; (2) invasive, but unknown stage; and (3) regional or distant stage disease.

: Patients enrolled in Medicaid <12 months before diagnosis were at greater risk of breast (odds ratio [OR] = 2.70; 95% confidence interval [95% CI] = 1.22-5.99) and lung (OR = 2.18; 95% CI = 1.45-3.29) cancer diagnosis in the month of death than Medicare only patients. Similarly, patients with a history of Medicaid enrollment had a high risk of diagnosis with invasive, but unknown breast, lung, and prostate cancer stage. Patients enrolled in Medicaid following diagnosis had a higher risk of late stage colorectal (OR = 1.30; 95% CI = 1.01-1.67), breast (OR = 2.12; 95% CI = 1.60-2.82), and lung (OR = 1.33; 95% CI = 1.02-1.75) cancer relative to Medicare only patients.

There is a preponderance of cancer diagnosis at death and cancer diagnosis with invasive but unknown stage in the Medicaid population, but the appropriateness of these diagnoses is unclear. Late-stage cancer tends to precipitate Medicaid enrollment.