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Table 1 Multimorbidity-Weighted Index Conditions and the Accuracy, Source, and Type of Validation for Respective ICD-9 Codes for the 10 Most Prevalent Conditions in Medicare claims; 2014

From: Comprehensive review of ICD-9 code accuracies to measure multimorbidity in administrative data

Organ systemDiagnosisICD-9 codes found in literature searchSource of ValidationaRecord TypeSample Size in StudyAlgorithmAccuracy (Sensitivity, Specificity, PPV, NPV, Kappab)
CardiovascularHypertension401.x-405.xxChart reviewDisease registry1842 claimsSENS: 65%
SPEC: 90%
PPV: 95%
NPV: 50%
Kappa: 0.45 [15]
401.x-405.xx, 437.2; exclusion: 250.xx, 430–436, 437.1, 437.9, 438.xxChart reviewInpatient, outpatient76Any claim up to 9 claimsPPV: 93% [16]
EndocrineElevated cholesterol/Hyperlipidemia272.0–272.4Chart reviewOutpatient1176≥1 outpatientSENS: 85%
SPEC: 85%
Kappa: 0.70 [17]
272.0–272.4Chart reviewDisease registry1842 claimsSENS: 95%
SPEC: 90%
PPV: 90%
NPV: 95%
Kappa: 0.85 [15]
OphthalmologicCataract366–366.4Construct validity [18]N/A
13.11, 13.19, 13.20, 13.30, 13.41, 13.42, 13.43, 13.59, 13.69, 13.71Construct validity [19]N/A
EndocrineDiabetes250.xxChart reviewOutpatient1176≥1 outpatient claimSENS: 97%
SPEC: 96%
Kappa: 0.92 [17]
250.xxChart reviewDisease registry1842 claimsSENS: 91%
SPEC: 100%
PPV: 100%
NPV: 90%
Kappa: 0.90 [15]
250.00–250.93Chart reviewAny encounter465(1) One claim; (2) Two claimsSENS: (1) 92%; (2) 64%
SPEC: (1) 99%; (2) 99%
PPV: (1) 94%; (2) 95% [20]
MusculoskeletalOsteoarthrosis715.xxConstruct validity [21]N/A
EndocrineHypothyroidism244.0, 244.1, 244.9Construct validity [22]N/A
RenalChronic kidney disease, polycystic kidney disease403.xx, 405.× 1, 582.xx, 583.xx, 585.x, 586, 593.9Chart reviewOutpatient1176≥1 outpatient claimSENS: 62%
SPEC: 98%
Kappa: 0.62 [17]
585.x, 586 (chronic renal failure)Chart reviewInpatient7050(1) Any claim; (2) Primary claimSENS: (1) 83%; (2) 85%
PPV: (1) 70%; (2) 61% [23]
585.x,
403.xx, 404.xx, 583.81, 581.81, 250.40, 250.42, 250.80, 250.82
Chart reviewInpatient, outpatient1186Any claimPPV: 63%
NPV: 54% [24]
753.12, 753.13, 753.14 (Polycystic kidney disease)Chart reviewDisease registry1842 claimsSENS: 100%
SPEC: 90%
PPV: 90%
NPV: 100%
Kappa: 0.90 [15]
(1) 250.40, 250.41, 250.42, 250.43 (diabetic nephropathy); (2) 403.xx, 404.xx (hypertensive nephropathy); (3) 572.4, 580.xx, 584.xx, 580.0, 580.4, 580.89, 580.9, 582.4, 791.2, 791.3 (acute renal failure); (4) 582.xx, 583.xx, 585.x, 586, 587 (chronic renal insufficiency)Chart reviewMedicare claims1852Any claimSEN: (1) 3%; (2) 7%; (3) 5%; (4) 12%
SPEC: (1) 99%; (2) 99; (3) 100%; (4) 99%
PPV: (1) 86%; (2) 95%; (3) 97%; (4) 97%
NPV: (1) 32%; (2) 33%; (3) 33%; (4) 35% [25]
PulmonaryChronic obstructive pulmonary disease (COPD)491.xx-494.x, 496Chart reviewInpatient7050(1) Any claim; (2) Primary claimSENS: (1) 85%; (2) 79%
PPV: (1) 87%; (2) 68% [23]
491.xx, 492.x, 496Chart reviewInpatient, outpatient12,127(1) ≥2 outpatient or ≥ 1 inpatient; (2) ≥3 outpatient or ≥ 2 inpatientPPV: (1) 64%; (2) 72% [26]
491.xx, 492.x, 496Chart reviewInpatient1221Primary claim of 491, 492, or 496PPV: 50% [17]
490–492.x, 493.22, 496, 518.81, 518.82, 518.84, 799.1Chart reviewInpatient(1) 50; (2) 46; (3) 29; (4) 20(1) Age ≥ 25, Primary claim of 490, 491.x, 492.x, 493.22, 496OR Primary claim of 518.81, 518.82, 518.84, 799.1 AND secondary claim of 490, 491.x, 492.x, 493.22, 496; (2) Age ≥ 40, Primary claim of 491.x (except for 491.20), 492.x, 493.22, 496 OR primary claim of 518.81, 518.82, 518.84 AND secondary claim of 491.x (except for 491.20), 492.x, 493.22, 496; (3) Age ≥ 40, primary claim of 491.x, 492.x, 496; (4) Age ≥ 40, primary claim of 491.21SENS: (1) 25%; (2) 24%; (3) 15%; (4) 12%
SPEC: (1) 100%; (2) 100%; (3) 100%; (4) 100%
PPV: (1) 81%; (2) 85%; (3) 86%; (4) 97%
NPV: (1) 94%; (2) 94%; (3) 93%;
(4) 93% [27]
490, 491.xx (all except 491.8), 492.x, 493.xx, 496Chart reviewOutpatient1176≥1 outpatient claimSENS: 81%
SPEC: 92%
Kappa: 0.68 [28]
CardiovascularCongestive heart failure(1) 398.91, 402.×1, 404.× 1, 404.× 3, or 428.xx; (2) 428.xxChart reviewInpatient908(1) Any claim;
(2) Primary claim
SENS: (1A) 94%; (1B) 55%; (2A) 91%; (2B) 48%
PPV: (1A) 43%; (1B) 86%; (2A) 43%; (2B) 86% [29]
398.91, 402.01, 402.11, 402.91, 404.01, 404.03, 404.11,
404.13, 404.91, 404.93, 425.x, 428.xx
Chart reviewInpatient497Primary claimSENS: 20%
SPEC: 100%
PPV: 79%
NPV: 94% [30]
398.91, 402.01, 402.11, 402.91, 404.01, 404.03, 404.11, 404.13, 404.91, 404.93, 425.4–425.9, 428.xxChart reviewInpatient, outpatient172(1) Any claim in 12-month window;
(2) Any claim in 24-month window
SENS: (1) 90%; (2) 90%
SPEC: (1) 95%; (2) 94%
PPV: (1) 72%; (2) 69%
NPV: (1) 99%; (2) 98% [31]
(1) 428.xx; (2) 402.xx or 428.xx; (3) 398.97, 402.×1, 404.xx, 415.0, 416.9,
425.4, 428.xx, 429.4, 514, 518.4, 786.0x
Chart reviewInpatient5083Any claimSENS: (1) 63%; (2) 66%; (3) 67%
SPEC: (1) 95%; (2) 93%; (3) 93%
PPV: (1) 84%; (2) 79%; (3) 77%
NPV: (1) 87%; (2) 88%; (3) 88% [32]
398.91, 402.×1, 402.×3, 404.× 1, 404.×3, 422.90, 425.4, 425.9, 428.xxChart reviewInpatient, outpatient400≥1 Primary Discharge or ≥ 3 Secondary Discharge or ≥ 2 Outpatient or ≥ 3 ED or ≥ 2 Secondary Discharge + ≥1 Outpatient ClaimSENS: 62%
SPEC: 99%
PPV: 69%
NPV: 98% [33]
398.91, 402.01, 402.11, 402.91, 404.01, 404.03, 404.11, 404.13, 404.91, 404.93, 414.8, 428.xxChart reviewOutpatient1176≥1 outpatientSENS: 77%
SPEC: 99%
Kappa: 0.74 [17]
428.xxChart reviewDisease registry1842 claimsSENS: 87%
SPEC: 100%
PPV: 100%
NPV: 85%
Kappa: 0.85 [15]
402.01, 402.11, 402.91, 428.0–428.9xChart reviewInpatient7050(1) Any claim;
(2) Primary claim
SENS: (1) 89%; (2) 85%
PPV: (1) 71%; (2) 87% [23]
(1) 428.xx; (2) 428.xx with other codes; (3) 402.01, 402.11, 425.x, 429.3, and 514Systematic reviewInpatient, outpatient35Various algorithms due to systematic reviewPPV: (1) 84–100%; (2) 77–79%; (3) 14–30% [34]
CardiovascularAtrial fibrillation427.31 (atrial fibrillation) or 427.32 (atrial flutter)Chart reviewInpatient, outpatient, emergency department3001 inpatient or 2 outpatient or emergency departmentPPV: 96% [35]
427.3xChart reviewOutpatient1176≥1 outpatientSENS: 80%
SPEC: 99%
Kappa: 0.81 [17]
427.31, 427.32Systematic reviewInpatient, outpatient16Various algorithms due to systematic reviewSENS: 57–95%
PPV: 70–96% [34]
  1. aIf the source of validation was a systematic review; the sample size refers to the number of studies included
  2. bThe number within the bracket following the accuracy values indicates the citation number for the reference