Assessing Hospital-Associated Deaths From Discharge Data

TLDR

Several lines of evidence suggest that chronic disorders are underreported for patients with life‑threatening conditions. The study assessed whether 30‑day mortality is more informative than inpatient mortality and whether additional discharge diagnoses clarify death rates. Researchers examined elderly Medicare hospitalizations for stroke, bacterial pneumonia, myocardial infarction, and congestive heart failure, which account for 30.8 % of Medicare 30‑day mortality. Inpatient mortality exceeded 30‑day mortality, varied by state, and was inflated by longer stays; additional diagnoses such as shock and pneumonia increased mortality but were not captured at admission, while chronic disease diagnoses were paradoxically linked to lower risk, underscoring the bias of inpatient death rates and the need for caution when using discharge diagnoses to adjust hospital mortality. JAMA 1988;260:2240‑2246.

Abstract

To assess the meaning of hospital-associated death rates, we studied whether mortality within 30 days of hospital admission (30-day mortality) is more informative than inpatient mortality and whether detailed assessment of additional discharge diagnoses helps in understanding death rates. We examined hospitalizations for elderly Medicare patients with principal diagnoses of stroke, bacterial pneumonia, myocardial infarction, and congestive heart failure; these conditions account for 30.8% of Medicare 30-day mortality. Average hospital stays for these conditions were 99.0% longer, and inpatient mortality was 25.0% higher in New York than in California, but 30-day mortality was 1.6% higher in California. We conclude that inpatient death rates depend on length-of-stay patterns and give a biased picture of mortality. Additional diagnoses such as shock and pneumonia were strongly associated with increased mortality, but Medicare data do not reveal which patients had these conditions at the time of admission. Recorded diagnoses of chronic diseases such as hypertension, diabetes mellitus, obesity, benign prostatic hypertrophy, and osteoarthritis were commonly associated with<i>reduced</i>risk of death; such reduced risk is not clinically plausible. Several lines of evidence suggest that chronic disorders are underreported for patients with life-threatening disorders. We recommend great caution in using discharge diagnoses of comorbid conditions to adjust hospital death rates for clinical differences in the patient populations. (<i>JAMA</i>1988;260:2240-2246)