Validation of Hypertensive Disorders During Pregnancy: ICD-10 Codes in a High-burden Southeastern United States Hospital

Abstract

Background: Identification of hypertensive disorders in pregnancy research often uses hospital International Classification of Diseases v. 10 (ICD-10) codes meant for billing purposes, which may introduce misclassification error relative to medical records. We estimated the validity of ICD-10 codes for hypertensive disorders during pregnancy overall and by subdiagnosis, compared with medical record diagnosis, in a Southeastern United States high disease burden hospital. Methods: We linked medical record data with hospital discharge records for deliveries between 1 July 2016, and 30 June 2018, in an Atlanta, Georgia, public hospital. For any hypertensive disorder (with and without unspecified codes) and each subdiagnosis (hemolysis, elevated liver enzymes, and low platelet count [HELLP] syndrome, eclampsia, preeclampsia with and without severe features, chronic hypertension, superimposed preeclampsia, and gestational hypertension), we calculated positive predictive value (PPV), negative predictive value (NPV) sensitivity, and specificity for ICD-10 codes compared with medical record diagnoses (gold standard). Results: Thirty-seven percent of 3,654 eligible pregnancies had a clinical diagnosis of any hypertensive disorder during pregnancy. Overall, ICD-10 codes identified medical record diagnoses well (PPV, NPV, specificity >90%; sensitivity >80%). PPV, NPV, and specificity were high for all subindicators (>80%). Sensitivity estimates were high for superimposed preeclampsia, chronic hypertension, and gestational hypertension (>80%); moderate for eclampsia (66.7%; 95% confidence interval [CI] = 22.3%, 95.7%), HELLP (75.0%; 95% CI = 50.9%, 91.3%), and preeclampsia with severe features (58.3%; 95% CI = 52.6%, 63.8%); and low for preeclampsia without severe features (3.2%; 95% CI, 1.4%, 6.2%). Conclusions: We provide bias parameters for future US-based studies of hypertensive outcomes during pregnancy in high-burden populations using hospital ICD-10 codes.

Improving preeclampsia risk prediction by modeling pregnancy trajectories from routinely collected electronic medical record data

“…This is likely due to the intended function of ICD codes being for billing, not diagnostic purposes 51 . Specifically, previous studies have shown that using ICD codes alone to identify preeclampsia patients performed poorly when compared to the gold standard of chart review 52 , 53 . Indeed, to identify as many PE cases as possible, ICD codes should be combined with EMR records (such as vitals and laboratory results).…”

Pregnancy-related cardiovascular conditions and outcomes in a United States Medicaid population

“…There is also recent research suggesting that the ICD-10 codes for pre-eclampsia without severe features had low sensitivity. 23 Other studies have demonstrated high validity of Medicaid data in research. 24 In this analysis, we have no data to validate diagnoses and rely on the accuracy of the claims.…”

“…This probably underestimated the validity of the data as they only used one hospital’s data records for cross-checking. There is also recent research suggesting that the ICD-10 codes for pre-eclampsia without severe features had low sensitivity 23. Other studies have demonstrated high validity of Medicaid data in research 24.…”

Association of Concomitant Gestational Hypertensive Disorders and Gestational Diabetes With Cardiovascular Disease

“… 48 The definitions of GHTD based on ICD codes have also been shown to be valid. 49 We did not have enough power to examine the subtypes of GHTD (preeclampsia/eclampsia and gestational hypertension) individually. We used a composite cardiovascular outcome, which limits our ability to understand the associations of GD and/or GHTD with specific individual cardiovascular outcomes, and thus which outcome may drive the observed association.…”