Role of quality measurement in inappropriate use of screening for colorectal cancer: retrospective cohort study

Abstract

Objective: To examine whether the age based quality measure for screening for colorectal cancer is associated with overuse of screening in patients aged 70-75 in poor health and underuse in those aged over age 75 in good health.

Design: Retrospective cohort study utilizing electronic data from the Veterans Affairs (VA) Health Care System, the largest integrated healthcare system in the United States.

Setting: VA Health Care System.

Participants: Veterans aged ≥ 50 due for repeat average risk colorectal cancer screening at a primary care visit in fiscal year 2010.

Main outcome measures: Completion of colonoscopy, sigmoidoscopy, or fecal occult blood testing within 24 months of the 2010 visit.

Results: 399,067 veterans met inclusion/exclusion criteria (mean age 67, 97% men). Of these, 38% had electronically documented screening within 24 months. In multivariable log binomial regression adjusted for Charlson comorbidity index, sex, and number of primary care visits, screening decreased markedly after the age of 75 (the age cut off used by the quality measure) (adjusted relative risk 0.35, 95% confidence interval 0.30 to 0.40). A veteran who was aged 75 and unhealthy (in whom life expectancy might be limited and screening more likely to result in net burden or harm) was significantly more likely to undergo screening than a veteran aged 76 and healthy (unadjusted relative risk 1.64, 1.36 to 1.97).

Conclusions: Specification of a quality measure can have important implications for clinical care. Future quality measures should focus on individual risk/benefit to ensure that patients who are likely to benefit from a service receive it (regardless of age), and that those who are likely to incur harm are spared unnecessary and costly care.

Fig 1 Relation between age, health status, and screening (n=399 067). In a 75 year old man, Charlson index of 0 indicates life expectancy >10 years, Charlson index of 1-3 indicates life expectancy of 5-10 years, and Charlson index ≥4 indicates life expectancy <5 years

Fig 2 Screening at age 75 v age 76 (n=21 499)

Fig 3 Screening by age (n=399 067) adjusted for sex, Charlson comorbidity index, and number of primary care visits in 2010