Adverse Patient Safety Events: Costs of Adverse Patient Safety Events: Costs of Readmissions and Patient Outcomes Following Readmissions and Patient Outcomes Following

DischargeDischarge

Didem M. Bernard, Ph.D.Didem M. Bernard, Ph.D.

William E. Encinosa, Ph.D.William E. Encinosa, Ph.D.

Patient Safety EventsPatient Safety Events

IoM estimated that between 44,000 and 98,000 people die in IoM estimated that between 44,000 and 98,000 people die in hospitals each year as a result of medical errorshospitals each year as a result of medical errors

Medical errors is the eighth leading cause of death in the U.S.Medical errors is the eighth leading cause of death in the U.S.

IoM recommended at least a 50% reduction in medical errors IoM recommended at least a 50% reduction in medical errors over 5 yearsover 5 years

BackgroundBackground

Medical injuries during hospitalizations lead to excess Medical injuries during hospitalizations lead to excess length of stay, charges and mortality (Zhan and Miller, length of stay, charges and mortality (Zhan and Miller, 2003)2003)

Whether adverse patient safety events have a significant Whether adverse patient safety events have a significant impact on patient outcomes and costs following impact on patient outcomes and costs following discharge is less cleardischarge is less clear

Research QuestionsResearch Questions

Do adverse patient safety events during Do adverse patient safety events during hospitalizations have an effect on patient hospitalizations have an effect on patient outcomes following discharge?outcomes following discharge?

Are there long-term costs associated with Are there long-term costs associated with potentially preventable adverse medical events?potentially preventable adverse medical events?

Patient Safety IndicatorsPatient Safety Indicators

We use the AHRQ Patient Safety Indicators (PSI) developed by the We use the AHRQ Patient Safety Indicators (PSI) developed by the UCSF- Stanford Evidence-Based Practice Center (EPC) and UC-UCSF- Stanford Evidence-Based Practice Center (EPC) and UC-Davis (2003).Davis (2003).

EPC selected 14 indicators among 63 complication indicators usingEPC selected 14 indicators among 63 complication indicators using– Indicator validity results from the literatureIndicator validity results from the literature– Empirical analyses of the precision and reliability of the Empirical analyses of the precision and reliability of the

candidate PSIscandidate PSIs– Review of potential indicators by 11 clinical panelsReview of potential indicators by 11 clinical panels

Patient Safety IndicatorsPatient Safety Indicators

1 Anesthesia Complications *

2 Accidental Puncture or Laceration During Procedure

3 Foreign Body Left In During Procedure*

4 Hemorrhage or Hematoma

5 Wound Dehiscence

6 Infection Due to Medical Care

7 Pulmonary Embolism and Deep Vein Thrombosis

* Labeled as medical errors

Patient Safety Indicators (cont.)Patient Safety Indicators (cont.)

8 Iatrogenic Pneumothorax*

9 Acute Respiratory Failure

10 Sepsis

11 Physiologic and Metabolic Derangements

12 Transfusion Reaction

13 Hip Fracture*

14 Decubitus Ulcer*

* Labeled as medical errors

Data Data

2002 California Hospital Discharge Data

AHRQ Healthcare Cost and Utilization Project (HCUP) State Inpatient Database (SID)

Hospital Inpatient Cost to Charge Ratios

Area Wage Index (CMS)

Number of Hospitals: 349

Analytic Sample and MethodsAnalytic Sample and Methods

Major Surgery Discharges (17<age<65)Major Surgery Discharges (17<age<65)

From February 1, 2002 to November 30, 2002From February 1, 2002 to November 30, 2002

Index admission: A major surgery admission with no hospitalizations Index admission: A major surgery admission with no hospitalizations in a 30 day window prior to the admission date (N=602,361)in a 30 day window prior to the admission date (N=602,361)

Readmission: Any hospitalization within 30 days of initial dischargeReadmission: Any hospitalization within 30 days of initial discharge

Patient OutcomesPatient Outcomes

Probability of readmissionsProbability of readmissions

Probability of death during index admission Probability of death during index admission

Probability of death during any readmission within 30 Probability of death during any readmission within 30 days of initial dischargedays of initial discharge

Costs of Adverse Patient Safety EventsCosts of Adverse Patient Safety Events

Index admission costsIndex admission costs

Costs of readmissionsCosts of readmissions

Total costs for index admissions and readmissions Total costs for index admissions and readmissions within 30 days following dischargewithin 30 days following discharge

Basic Model: Hospital CostsBasic Model: Hospital Costs

i=personi=persony= cost of hospitalization*y= cost of hospitalization*PSI= (0,1) indicator equals 1 if patient has at least onePSI= (0,1) indicator equals 1 if patient has at least oneadverse patient safety eventadverse patient safety eventx=control variablesx=control variables

* * Index admission, readmission or total hospital costsIndex admission, readmission or total hospital costs

Basic Model: Patient OutcomesBasic Model: Patient Outcomes

i=personi=persony=(0,1) indicator equals 1 if patient is readmitted within y=(0,1) indicator equals 1 if patient is readmitted within

30 days of discharge*30 days of discharge*PSI= (0,1) indicator equals 1 if patient has at least onePSI= (0,1) indicator equals 1 if patient has at least oneadverse patient safety eventadverse patient safety eventx=control variablesx=control variables

* y=(0,1) indicator equals 1if patient dies during hospitalization* y=(0,1) indicator equals 1if patient dies during hospitalization

Control VariablesControl Variables

Patient: age, sex, race/ethnicity, transfer admission, Patient: age, sex, race/ethnicity, transfer admission, emergency admission, 30 chronic conditions, MDC, emergency admission, 30 chronic conditions, MDC, zipcode level median household incomezipcode level median household income

Hospital: teaching status, ownership type, bedsizeHospital: teaching status, ownership type, bedsize

Market: Health Service Area dummiesMarket: Health Service Area dummies

Patient OutcomesPatient Outcomes

PSI=0PSI=0 PSI=1PSI=1

Live dischargeLive discharge 84.55%84.55% 63.03%63.03%

Death during Death during index admissionindex admission 0.86%0.86% 5.97%5.97%

ReadmissionReadmission 14.14%14.14% 28.32%28.32%

Death during Death during readmissionreadmission 0.46%0.46% 2.68%2.68%

NN 583,836583,836 18,889 18,889

Average CostsAverage Costs

Index Index HospitalizationHospitalization ReadmissionReadmission Total CostsTotal Costs

PSI=0PSI=0 $12,579$12,579 $17,927 $17,927 $15,198$15,198

PSI=1PSI=1 $31,096$31,096 $33,445$33,445 $41,510$41,510

DifferenceDifference 147%147% 87%87% 173%173%

EstimationEstimation

Costs: GLM (Generalized Liner Method) log-link with Gamma Costs: GLM (Generalized Liner Method) log-link with Gamma distribution (Manning and Mullahy, 2001) distribution (Manning and Mullahy, 2001)

Patient Outcomes: Logit regressionsPatient Outcomes: Logit regressions

Simulation results: Simulation results: A : Predicted costs/outcomes with PSI=1A : Predicted costs/outcomes with PSI=1B : Predicted costs/outcomes with PSI=0B : Predicted costs/outcomes with PSI=0(A – B) : Predicted costs/outcomes due to adverse patient safety events(A – B) : Predicted costs/outcomes due to adverse patient safety events

Simulation Results: OutcomesSimulation Results: Outcomes

Death Death during index during index hospitalizationhospitalization

Death during Death during readmissionreadmission

Death within Death within 30 days of 30 days of dischargedischarge

PSI=0PSI=0 0.92%0.92% 3.4% 3.4% 1.4%1.4%

PSI=1PSI=1 1.96%1.96% 5.2%5.2% 2.8%2.8%

% Difference% Difference 1.04%*1.04%* 1.8%*1.8%* 1.4%*1.4%*

* Significantly different from zero at the 99% level

Simulation Results: Outcomes (cont.)Simulation Results: Outcomes (cont.)

Probability of Probability of

readmissionreadmission

PSI=0PSI=0 15.1%15.1%

PSI=1PSI=1 20.1%20.1%

DifferenceDifference 5.0%*5.0%*

* Significantly different from zero at the 99% level

Simulation Results: CostsSimulation Results: Costs

Index Index HospitalizationHospitalization ReadmissionReadmission Total CostsTotal Costs

PSI=0PSI=0 $12,801$12,801 $18,264 $18,264 $15,618$15,618

PSI=1PSI=1 $21,190$21,190 $26,198$26,198 $26,607$26,607

PSI COSTPSI COST

$8,388*$8,388*

(232)(232)

$7,933*$7,933*

(529)(529)

$10,989*$10,989*

(284)(284)

% Difference% Difference 65.5%65.5% 43.4%43.4% 70.4%70.4%* Significantly different from zero at the 99% level

SummarySummary

Excess costs and adverse outcomes of adverse patient safety Excess costs and adverse outcomes of adverse patient safety events are not limited to the initial hospitalization events are not limited to the initial hospitalization

Adverse patient safety events during hospitalizations lead toAdverse patient safety events during hospitalizations lead to– Higher probability of readmissionsHigher probability of readmissions– Higher probability of in-hospital death following dischargeHigher probability of in-hospital death following discharge– Higher inpatient costs following dischargeHigher inpatient costs following discharge

Policy ImplicationsPolicy Implications

A reduction in adverse patient safety eventsA reduction in adverse patient safety events

will not only improve quality of care but also will not only improve quality of care but also reduce long-term health care costsreduce long-term health care costs