DALLAS Inpatients treated by hospitalists have significantly shorter average lengths of stay than do those with the same conditions treated by office-based general internists or family physicians, according to the largest comparative outcome study to date involving the three physician groups.
The briefer length of stay (LOS) in the hospitalist-treated patients did not come at a cost of increased inpatient mortality or 14-day readmissions, which were similar across all three physician groups, Dr. Peter K. Lindenauer said at the annual meeting of the Society of Hospital Medicine.
Hospital costs were lower for hospitalists than for general internists, but similar for hospitalists and family physicians, reported Dr. Lindenauer, a hospitalist at Baystate Medical Center, Springfield, Mass.
"Based on these findings, we believe that the hospitalist model of care will continue to be attractive to hospitals seeking to improve throughput while reducing costs," he said.
Dr. Lindenauer presented an observational retrospective cohort study involving 76,296 adult inpatients at 45 U.S. hospitals. They were cared for by 284 hospitalists, 993 general internists, and 971 family physicians. To facilitate comparisons, patients had to have one of seven common presenting diagnoses: acute MI, chest pain, heart failure, ischemic stroke, urinary tract infection, pneumonia, or acute exacerbation of chronic obstructive pulmonary disease.
The investigators used multivariate regression models to examine the impact of physician specialty on outcomes while controlling for potential confounders including patient age, comorbidities, gender, ethnicity, and hospital size and location.
Mean LOS ranged from 4.7 days for hospitalists to 5.2 days for general internists, with costs ranging from a low of $7,077 for family physicians to $8,078 for hospitalists. The 14-day readmission rate ranged from 6.3% for hospitalists to 6.9% for general internists. Inpatient mortality was the lowest for family physicians at 4.1% and highest for general internists at 4.5%.
After adjustment for potential confounders, the mean LOS for hospitalists was 0.6 and 0.4 days shorter than for general internists and family physicians, respectively. Those differences were significant. Costs averaged $417 less per case for hospitalists versus general internists.
Dr. Lindenauer and his coworkers were particularly interested in learning whether the outcome differences among the three groups of physicians could be explained simply by the substantial differences in patient volume. Hospitalists treated an average of 75 patients per year with one of the seven index diagnoses, compared with 30 for general internists and 20 for family physicians. Three-quarters of all hospitalists cared for 40 or more patients per year with these diagnoses, compared with 23% of internists and 9% of family physicians.
However, when the analyses were restricted to those general internists and family physicians who met the 40-patient-per-year criteria, it was apparent that patient volume explained only a minority of the outcome differences.
For example, the difference in average hospital costs between hospitalists and general internists dropped from $417 to $276 when only high-volume internists were considered. LOS was only modestly shorter for high-volume internists than internists overall, and there was no difference at all in length of stay between all family physicians and high-volume family physicians.
Dr. Robert Wachter praised this as "a spectacular studyobviously the largest to date and probably the most persuasive study to date of an efficiency benefit."
The most surprising finding is the lack of a cost difference between family physicians and hospitalists, given the hospitalists' significantly shorter LOS, which is traditionally a major determinant of costs, observed Dr. Wachter, professor and associate chairman of medicine at the University of California, San Francisco.
At higher levels, patient volume explained only a minority of the outcome differences. DR. LINDENAUER