Deborah Wingard, W. Susan Cheng,

Donna Kritz-Silverstein, Elizabeth Barrett-Connor

Sensitivity and Specificity of Death Certificates for Diabetes:

As Good as it Gets?

Insulin Hexamer

Introduction

Diabetes sixth major cause of death in US

Among diabetic population, diabetes listed 20%-50% anywhere on death certificates

Mortality data used for policy decisions Disease reportingBurden of diseaseFunding

Introduction

Death Certificates for Disease ReportingDeath Certificates for Disease ReportingNo standard formNo standard formNo standard trainingNo standard training Inadequate fieldsInadequate fieldsNot regular physicianNot regular physician

Purpose

Examine change in accurate reporting of diabetes on death certificate

Potential factors improving reporting:SexAge, year, place, & cause of deathDiabetes medication use

Methods

Rancho Bernardo cohort

Age 30+ at enrollment (1972-74)

Mortality data through 2003follow-up: 1-30 yearsmean = 15.2 + 7.6 yrs

Death certificates for 3209 decedents

Methods

Diagnosed Diabetes Periodic clinic visits

1972-74, 1984-86, 1992-96, 1997-99Blood work & self-report

Mailed questionnaires 1982, 1988, 1993, 1996, 1998

Diabetes Listed on Death Certificate Anywhere Cause of Death

Death Certificates

Underlying cause of death

Consequence leading to death

Significant conditions

. .

. .

. .

. .. .

. .

3209 w/Death CertificateAnd ICD9 Codes

Diabetes(n=322)

No Diabetes(n=2887)

Diabetes(n=112)

No Diabetes(n=210)

Diabetes(n=56)

No Diabetes(n=2831)

Diabetes Listed On Death Certificates

Diabetes Reported During Study

Methods

Sensitivity and specificityUnadjusted and Stratified

SexAge at deathYear of deathPlace of deathCause of deathDiabetes medication use

Accuracy of Reporting:Sensitivity and Specificity

Diabetes on Death Certificate

Yes No

Diabetes Status

Ever Reported (Yes) A B A+B

Never Reported (No) C D C+D

Sensitivity: A/(A+B)

Specificity: D/(C+D)

Logistic Regression

Sample: 378 diabetic decedentsSample: 378 diabetic decedents

Outcome: Death certificate reporting diabetesOutcome: Death certificate reporting diabetes

Predictors of Better Reporting:Predictors of Better Reporting:SexSexAge, year, place, cause of deathAge, year, place, cause of deathDiabetes medication useDiabetes medication use

3209 w/Death CertificateAnd ICD9 Codes

Diabetes(n=322)

No Diabetes(n=2887)

Diabetes(n=112)

No Diabetes(n=210)

Diabetes(n=56)

No Diabetes(n=2831)

Diabetes Listed On Death Certificates

Diabetes Reported During Study

Descriptives of Decedents

Mean age (yrs)At Visit 1: 65At Death: 82

Sex (%)Men: 51Women: 49

Descriptives of Decedents

Place of Death (%)Hospital: 67Home: 22Other: 11

Year of Death (%)1972-81: 221982-91: 411992-03: 37

Cause of Death (%)Cause of Death (%)CVD: 41CVD: 41Diabetes: 1Diabetes: 1Cancer: 23Cancer: 23Other: 35Other: 35

Descriptives of Decedents

DiabetesNo Diabetes

Age at Enrollment (yrs): 64.2 65.4

Men (%): 61 50

CVD deaths (%): 44 41

No difference: age at death, place & year of death

Results: Accuracy of Reporting 322 decedents with reported diabetes

168 listed diabetes anywhere on death certificates 56 did not report diabetes

Sensitivity of diabetes reporting Anywhere: 34.7% Cause of Death: 6.2%

Specificity of diabetes reporting Anywhere: 98.1% Cause of Death: 99.8%

Stratified SensitivityCharacteristic N Sensitivity (%)Sex

Men 1641 32Women 1568 39

Age at Death (yrs)<76 (ref) 863 3777-82 719 3283-88 856 4089+ 771 29

Year of Death1972-81 (ref) 714 371982-91 1324 341992-03 1171 35

Stratified Sensitivity (cont)Characteristic N Sensitivity(%)

Cause of Death

All Other 1862 23

CVD 1324 39

Place of Death

Other (ref) 366 26

Hospital 2136 36

Home 689 37

Diagnosis

MD only 139 17

MD + medication use 183 49

Summary of Results

Higher sensitivity for diabetes reporting:Deaths in hospitals, homeCVD as underlying causeDiabetes medication use

Sensitivity did not vary by:SexAge of deathYear of death

Logistic Regression Among Diabetic Decedents (n=378)

Characteristic OR 95%CI

Age 1.0 0.9, 1.0

Men vs. women 1.5 1.0, 2.2

Year of Death 1.0 0.9, 1.0

Logistic Regression Among Diabetic Decedents (n=378)

Characteristic OR 95%CICause of Death

CVD v. all other 1.4 0.9, 2.2

Place of DeathHospital v. other 1.0 0.5, 2.2Home v. other 1.0 0.6, 1.9

DiagnosisDb med. use v. Dx only 4.8 2.8, 8.1

CVD v. all other cause of death by decade of death

37 37

33 34

49

27

0

5

10

15

20

25

30

35

40

45

50

1972-81 1982-91 1992-03

CVD

All Other Cause

Sen

sitiv

ity (

%)

Summary: US Population-Based

Author (year) N Years Ages Sensitivity (%)

MinnesotaPalumbo (1976) 1470 1945-70 6-70+ 32Ochi (1985) 428 1964-74 30-80+ 38Spratka (1993) 274 1978-88 =74 54

North DakotaBrousseau (1987) 552 1985 =77 45

WashingtonAnderson (1993) 282 1989-90 =69 41

Rancho BernardoPresent study 3209 1972-2003 =82 35

mean

Summary: US National

Author (year) N Years Ages Sensitivity (%)

Diabetic Eye DiseaseMMWR (1991) 569 1985-90 18+ 48

Mortality Follow-BackBild (1992) 2766 1986 25+ 38

NHANESGu (1998) 14,374 1975-93 25-75+ 36 (Men)

47 (Women)

Will (2001) 16,567 1986 25-75+ 38 16,593 1993 25-75+ 36

Summary: Studies Abroad

Author (year) N Years Ages Sensitivity (%)

Scotland

Waugh (1985) 1827 1985-88 15-75 70

Jamaica

Alleyene (1989)8799 1970-79 All 67

Portugal

Coeli (2002) 2974 1994 60-80+ 52

Strengths & Limitations

Limitations

Generalizability

White, middle class, good access to medical care

Results similar to other US based studies

StrengthsStrengths

Direct access to Direct access to individualsindividuals

Lengthy follow-up period Lengthy follow-up period

Recent dataRecent data

Conclusions

No overall improvement in diabetes reporting on death certificates

Better reporting observed in recent years (1992-2003) for CVD listed as cause of death

Persistent under-reporting of diabetes on death certificates leads to an underestimate of the burden of disease in the population

Questions?

Rancho Bernardo, CA

Table 1: Descriptives of Sample

Descriptives of DecedentsPlace of Death (%)

Hospital: 67 Home: 22 Other: 11

Year of Death (%) 1972-81: 22 1982-91: 41 1992-03: 37

Mean age (yrs) At Visit 1: 65 At Death: 82

Sex (%) Men: 51 Women: 49

Cause of Death (%)Cause of Death (%) CVD: 41CVD: 41 Diabetes: 1Diabetes: 1 Cancer: 23Cancer: 23 Other: 35Other: 35

Logistic Regression Among Diabetic Decedents (n=378)

Characteristic OR 95%CIAge 1.0 0.9, 1.0

Men vs. women 1.5 1.0, 2.2

Year of Death 1.0 0.9, 1.0

Cause of DeathCVD v. all other 1.4 0.9, 2.2

Place of DeathHospital v. other 1.0 0.5, 2.2Home v. other 1.0 0.6, 1.9

DiagnosisDb med. use v. Dx only 4.8 2.8, 8.1

Summary: US Based Studies

Author (year) N Years Ages Sensitivity (%)

Palumbo (1976) 1470 1945-70 6-70+ 32Ochi (1985) 428 1964-74 30-80+ 38Spratka (1993) 274 1978-88 =74 54Brousseau (1987) 552 1985 =77 45Anderson (1993) 282 1989-90 =69 41

National StudiesMMWR (1991) 569 1985-90 18+ 48Bild (1992) 2766 1986 25+ 38Gu (1998) 14,374 1975-93 25-75+ 36 (Men)

47 (Women)Will (2001) 16,567 1986 25-75+ 38

16,593 1993 25-75+ 36

mean

US Based Studies (Sensitivity %)

Local Studies Minnesota

Prospective (32%)Pop based (38%)Pop based (54%)

North DakotaPop based (45%)

WashingtonPop based (41%)

National Studies Diabetic Eye Disease (48%) Mortality Follow-back (38%) NHANES

36% Men, 47% Women