In a recent study, rapid response team implementation at 1 hospital was associated with only a 0.1% reduction in inpatient mortality from 2005 to 2018, characterized in the accompanying editorial as a “tepid” improvement. The editorialist postulated that an increase in the degree of illness of hospitalized patients might have masked a larger reduction that otherwise might have occurred. Impressions of greater patient acuity during the studied period might have been an artifact of efforts to document more comorbidities and complications, possibly facilitated by the change in diagnosis coding from the International Classification of Diseases, Ninth Revision (ICD-9) to the Tenth Revision (ICD-10).
We used inpatient data from every nonfederal hospital in Florida from the last quarter of 2007 through 2019. We studied hospitalizations for major therapeutic surgical procedures with lengths of stay ≥2 days. Using logistic regression with clustering by the Clinical Classification Software (CCS) code of the primary surgical procedure, we evaluated the trends for decreased mortality, changes in the prevalence of Medicare Severity Diagnosis Related Groups (MS-DRG) with complications or comorbidities (CC) or major complications or major comorbidities (MCC), and changes in the van Walraven index (vWI), a measure of patient comorbidities associated with increased inpatient mortality. Also incorporated in the modeling was the change from ICD-9 to ICD-10.
There were 3,151,107 hospitalizations comprising 130 distinct CCS codes and 453 MS-DRG groups among 213 hospitals. Despite a progressive increase of 4.1% per year in the odds of a CC or MCC (P = .001), there were no significant changes in the marginal estimates of in-house mortality over time (net estimated decrease, 0.036%; 99% confidence interval [CI], −0.168% to 0.097%; P = .49). There was also absence of a significantly greater fraction of discharges with vWI >0 attributable to the year of the study (odds ratio, 1.017 per year; 99% CI, 0.995–1.041). The changes in MS-DRG to those with CC or MCC were not increased significantly from either the ICD-10 coding change or the number of years after the change.
Consistent with the previous study, there was at most a small decrease in the mortality rate over a 12-year period. We found no reliable evidence that patients undergoing elective inpatient surgical procedures were any sicker in 2019 than in 2007. There were substantively more comorbidities and complications documented over time, but this was unrelated to the change to ICD-10 coding.