The inter-relationship between length-of-stay, readmission and death: impact on hospital outcomes P.J. Marang-van de Mheen, H.F. Lingsma, A. Bottle, S. Middleton, J. Kievit, E.W. Steyerberg

Disclosures No funding for this research No pay for talks, advice or conference attendence

Background Hospital mortality, readmission & Length-of-Stay (LOS) commonly used outcomes to measure quality of care Problem: interrelation between outcomes affecting interpretatation Deaths included in LOS models Deaths not included in readmission models Mortality models not adjusted for readmission and LOS

Purpose of the study 1.Disentangle the relationship between mortality, readmission and LOS, on patient and hospital level 2.Propose new measure to jointly report these 3 outcome measures to facilitate insight and evaluation of quality of care -> less ambiguous interpretation of hospital specific outcomes

Patients and outcomes Patients Global Comparators Project, 26 hospitals in 6 countries Patients discharged between All patients, stroke, heart failure and colorectal patients Outcomes: Mortality, readmission and prolonged LOS (>75 percentile)

Results: descriptives All patientsStrokeHeart FailureColorectal Number4,327,10583,16385,02435,537 Mortality rate3.1%13.6%6.7%5.0% Readmission (survivors) 7.8%7.3%16.9%10.6% Long LOS20.8%20.7% 22.6% Range of standardized outcomes at hospital level: Mortality: Readmission: Long LOS:

Results: relationships at patient level MortalityReadmission All patients Long LOS1.45 ( )1.37 ( ) Stroke patients Long LOS0.46 ( )1.16 ( ) Heart Failure patients Long LOS1.38 ( )1.17 ( ) Colorectal patients Long LOS1.31 ( )1.34 ( ) Odds Ratios adjusted for case-mix & center

Results: correlations at hospital level Mortality – readmission: r= p=0.76 Mortality – long LOS survivors: r=0.79 p<0.01 Readmission – long LOS survivors: r= p=0.33 Long LOS (survivors) – long LOS (deaths): r=0.77 p<0.01 Similar results for upper decile LOS

Composite measure based on 3 outcomes, 5 levels 1.Survivors, no readmission, normal LOS (best) 2.Survivors, no readmission, long LOS 3.Survivors, readmission, normal LOS 4.Survivors, readmission, long LOS 5.Deaths (worst) Literature evidence suggests that patients consider readmission as worse quality of care than long LOS Presented at expert meeting (N≈ 100) for agreement Analysed using ordinal regression – single standardized rate to compare hospitals

Variation in composite measure All patients: Stroke: Colorectal: HF: Upper decile LOS: similar, smaller variation

Results: correlation composite with individual outcomes Mortality: r=0.78 p<0.01 Readmission: r= p=0.72 Long LOS: r=0.98 p<0.01 Similar results when constructed with upper decile LOS

Composite measure versus individual outcomes Composite measure has similar or better efficiency to estimate hospital effect Rankability: reliability of ranking hospitals Rankability of composite measure is similar or better than individual measures

Conclusions and discussion Three outcomes: better total picture of quality of care Summary measure: Ordering based on content Good statistical properties to discriminate between hospitals Large influence of LOS? Similar results for upper decile LOS No weighting applied, but is possible Direction where to improve

Did we improve? More patients alive, without readmission & normal LOS => on average better care Smaller variance between hospitals => more uniform better care Similar for upper decile LOS