TABLE 1.

Assessments of the validity of ICD-9-CM–based algorithms for identifying pediatric SCD in U.S. healthcare databases

Author	Case definitiona	Study period and reference period for algorithm	Age group	Source of ICD-9-CM data	Validation data source	Validation results
(1) Algorithms using ≥1 inpatient or ≥2 outpatient claims or encounters
Halasa etal. (2007)30	1 inpatient claim or ≥2 outpatient claims ≥30 days apart with a diagnosis code for SCD Note ICD-9-CM codes of 282.41 and 282.42 were not included	10 years, 1995–2004, for both	Children, born in state, 19962003	Tennessee Medicaid claims, 1995–2004	Tennessee NBS data, 1996–2003	PPV 86.0% (312 confirmed cases out of 363 who met SCD case-finding algorithm) Sensitivity 91.2% (312 true positives and 32 false negatives among 344 children with SCD confirmed by NBS records)
Reeves et al. (2014)19	1 inpatient claim or ≥2 outpatient claims ≥1 day apart with SCD codes during 12-month period	1 year, 2010 or 2011, for both	Children, ages 0–18 years, born in state	Michigan Medicaid claims, 2010 and 2011	Michigan NBS data, 1987–2010	2010 data PPV 94.5% Sensitivity 90.2% Specificity 90.4% 2011 data PPV 94.5% Sensitivity 90.2% Specificity 90.4%
(2) Algorithm using 3 or more claims with ICD codes for SCD
Reeves et al. (2014)19	Presence of ≥3 claims (any setting) on separate dates with SCD codes during 12-month period	1 year, 2010 or 2011, for both	Children, ages 0–18 years	Michigan Medicaid claims, 2010 and 2011	Michigan NBS data, 1987–2010	2010 data: PPV 95.0% Sensitivity 90.7% Specificity 91.3% 2011 data: PPV 95.8% Sensitivity 89.7% Specificity 87.9%
Snyder etal. (2019)23	Presence of ≥3 claims any setting on separate dates with SCD codes during the 5-year period Additional ICD-9-CM code included: 282.6	5 years, 2004–2008, for both	Children and young adults, ages 0–21 years	Georgia Medicaid, Children’s Health Insurance Program, State Health Benefit Plan, Georgia hospital discharge data, 2004–2008	Children’s Healthcare of Atlanta medical and laboratory records, Georgia NBS records	PPV: 97.4% Sensitivity: 96.0% Specificity: 76.5% NPV: 68.2%
(3) Combinations of diagnosis codes with SCD-associated treatments, procedures, and complications
Snyder etal. (2019)23	≥2 claims on separate dates with SCD ICD-9-CM codes and ≥1 claim with code for an SCD-associated treatment, procedure, or complication Additional ICD-9-CM code included: 282.6	5 years, 2004–2008, for both	Children and young adults, ages 0–21 years	Georgia Medicaid, Children’s Health Insurance Program, State Health Benefit Plan, Georgia hospital discharge data, 2004–2008	Children’s Healthcare of Atlanta medical and laboratory records, Georgia NBS records	PPV: 97.4%, Sensitivity 85.8% Specificity: 79.0% NPV: 38.2%

Abbreviations: ED, emergency department; ICD-9-CM, International Classification of Diseases Version 9 Clinical Modification; NBS, newborn screening; NPV, negative predictive value; PPV, positive predictive value; SCD, sickle cell disease

^aAll case definitions include the following ICD-9 codes unless otherwise indicated: 282.60–282.69 and 282.41,282.42.