Date of Award

January 2018

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Jonathan N. Grauer

Abstract

The purpose of this study is to investigate the readmission patterns within 90 days of discharge following common orthopaedic conditions such as posterior lumbar fusion and geriatric hip fracture and compare them to long term admission patterns in a matched population in light of the current trend toward bundled payments for healthcare.

Posterior lumbar fusions performed and geriatric hip fractures both managed operatively and non-operatively in the first 9 months of 2013 were identified in the Healthcare Cost and Utilization Program National Readmissions Database. Patient demographics and readmissions were tracked for 90 days after the discharge. To estimate a basal admission rate in a matched population, the average daily admission rate in the last quarter of the year was calculated for a subset of patients who had their initial discharge in the first quarter of the year. A 5-day moving average of the percent of the initial cohort that was readmitted daily was calculated and compared to the basal admission rate.

Of 26,727 patients undergoing posterior lumbar fusion, 1,580 patients (5.91% of the study population) were readmitted within 30 days of discharge and 2,603 patients (9.74%) were readmitted within 90 days of discharge. Of all readmissions within 90 days, including multiple readmissions, 54.6% occurred in the first 30 days. However, if only counting readmissions above the baseline admission rate of a matched population for the 4th quarter of the year (0.08% of population/day), 89.8% occurred within the first 30 days with the 5-day moving average of readmissions reaching the basal admission rate at 40 days.

Of 85,838 patients age ≥ 65 who suffered a hip fracture, 10,287 (12.3% of the study population) were readmitted at least once within 30 days of discharge. 18,309 (21.2% of the study population) were readmitted at least once within 90 days. Of all readmissions, including multiple readmissions, within 90 days, 11,219 out of 23,186 (48.4%) occurred within 30 days. When counting readmissions above the baseline admission rate of a matched population (0.1% of population/day), 56.2% occurred within the first 30 days with the 5-day moving average of readmissions never reaching the basal admission rate within 90 days.

Although the number of readmissions after posterior lumbar fusion almost doubled between 30 and 90 days, accounting for a baseline rate of readmissions for this population significantly affected the perceived number readmitted due to the index operation. Conversely, the increase in readmissions following geriatric hip fracture was not significantly affected by baseline rate of admissions. Determining baseline readmission rates will be an important consideration as healthcare continues to move in the direction of bundled payments.

Comments

This thesis is restricted to Yale network users only. It will be made publicly available on 06/25/2100

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