Comparing morbidities of testing with a new index: screening colonoscopy versus core-needle breast biopsy

Focusing on outcomes of care alone may be too restrictive. Patients can experience morbidity that is important to them from health care processes themselves. However, many processes, such as testing and screening, have been little evaluated. This study's purpose was to assess the construct validity of a new preference-based index, the Testing Morbidities Index (TMI), by comparing two common cancer-related procedures in prior publications: screening colonoscopy and core-needle breast biopsy.

Women evaluating their breast biopsies (n = 100) were compared with men and women who had undergone screening colonoscopy (n = 109) after both groups completed the TMI. The TMI addresses physical and mental or emotional quality of life affected by test-specific aspects occurring before, during, or after any test. It has 7 domains and survey items. TMI scores can be scaled in various ways, including multi-attribute value theory-based patient or societal preferences, where 0 = dead and 1.0 = full health, as used here.

There was significantly greater morbidity from breast biopsy (mean, 0.84) than from screening colonoscopy (mean, 0.88) comparing overall TMI preference scores (P < .0001). Breast biopsy showed significantly worse morbidity (P = .005 to P < .0001) in most domains. Pain or discomfort before testing was worse for colonoscopy because of bowel preparation. The TMI showed no floor effect and an acceptable ceiling effect.

The TMI provides the first objective evidence comparing the morbidity of one cancer-related testing procedure with another. The TMI may be useful in assessments of medical care processes informative to institutions and imaging departments, shared decision-making scenarios, and economic analyses.