Development and Validation of ICD-10-CM-based Algorithms for Date of Last Menstrual Period, Pregnancy Outcomes, and Infant Outcomes

Abstract

Introduction and objective: Validation studies of algorithms for pregnancy outcomes based on International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) codes are important for conducting drug safety research using administrative claims databases. To facilitate the conduct of pregnancy safety studies, this exploratory study aimed to develop and validate ICD-10-CM-based claims algorithms for date of last menstrual period (LMP) and pregnancy outcomes using medical records.

Methods: Using a mother-infant-linked claims database, the study included women with a pregnancy between 2016-2017 and their infants. Claims-based algorithms for LMP date utilized codes for gestational age (Z3A codes). The primary outcomes were major congenital malformations (MCMs) and spontaneous abortion; additional secondary outcomes were also evaluated. Each pregnancy outcome was identified using a claims-based simple algorithm, defined as presence of ≥ 1 claim for the outcome. Positive predictive values (PPV) and 95% confidence intervals (CI) were calculated.

Results: Overall, 586 medical records were sought and 365 (62.3%) were adjudicated, including 125 records each for MCMs and spontaneous abortion. Last menstrual period date was validated among maternal charts procured for pregnancy outcomes and fewer charts were adjudicated for the secondary outcomes. The median difference in days between LMP date based on Z3A codes and adjudicated LMP date was 4.0 (interquartile range: 2.0-10.0). The PPV of the simple algorithm for spontaneous abortion was 84.7% (95% CI 78.3, 91.2). The PPV for the MCM algorithm was < 70%. The algorithms for the secondary outcomes pre-eclampsia, premature delivery, and low birthweight performed well, with PPVs > 70%.

Conclusions: The ICD-10-CM claims-based algorithm for spontaneous abortion performed well and may be used in pregnancy studies. Further algorithm refinement for MCMs is needed. The algorithms for LMP date and the secondary outcomes would benefit from additional validation in a larger sample.

Fig. 1

a Cohort creation flow diagram for women/pregnancies. DAPI Dynamic Assessment of Pregnancies and Infants, LMP last menstrual period. ^aHave continuous medical and pharmacy benefit coverage for a minimum of 6 months (182 days) prior to and including the estimated LMP through the end of pregnancy. ^bEarliest LMP occurring on or after 01JAN2016; end of pregnancy ending by 31DEC2017. ^cThis step determines women for whom Optum can seek medical charts for the pregnancy and outcome, assessed at the pregnancy episode level. Pregnancies among women enrolled in administrative services only plans were excluded because access to medical records was not allowed for patients in these plans. The final study population consisted only of women with pregnancies for whom Optum could seek medical charts. b Cohort creation flow diagram for infants. ^aSee Figure 1a for details of the study population creation. ^bThis is “multi-gestation” pregnancies that have livebirth(s) and stillbirth(s) (e.g. twins, one liveborn and one stillborn; quadruplets, some liveborn). ^cIncludes stillbirths, ectopic, molar, and abortions (“spontaneous,” “elective,” and “other” per DAPI definitions). ^dLinked pregnancies are pregnancies for which the mother and infant data could be linked. Forty-one linked infants were from pregnancies ending in a non-livebirth, possibly representing misclassification of how these pregnancies ended. ^eThis step determines infants for whom Optum can seek medical charts. Infants enrolled in administrative services only plans were excluded because access to medical records was not allowed for patients in these plans. The final study population consisted only of infants for whom Optum could seek medical charts

Fig. 1

a Cohort creation flow diagram for women/pregnancies. DAPI Dynamic Assessment of Pregnancies and Infants, LMP last menstrual period. ^aHave continuous medical and pharmacy benefit coverage for a minimum of 6 months (182 days) prior to and including the estimated LMP through the end of pregnancy. ^bEarliest LMP occurring on or after 01JAN2016; end of pregnancy ending by 31DEC2017. ^cThis step determines women for whom Optum can seek medical charts for the pregnancy and outcome, assessed at the pregnancy episode level. Pregnancies among women enrolled in administrative services only plans were excluded because access to medical records was not allowed for patients in these plans. The final study population consisted only of women with pregnancies for whom Optum could seek medical charts. b Cohort creation flow diagram for infants. ^aSee Figure 1a for details of the study population creation. ^bThis is “multi-gestation” pregnancies that have livebirth(s) and stillbirth(s) (e.g. twins, one liveborn and one stillborn; quadruplets, some liveborn). ^cIncludes stillbirths, ectopic, molar, and abortions (“spontaneous,” “elective,” and “other” per DAPI definitions). ^dLinked pregnancies are pregnancies for which the mother and infant data could be linked. Forty-one linked infants were from pregnancies ending in a non-livebirth, possibly representing misclassification of how these pregnancies ended. ^eThis step determines infants for whom Optum can seek medical charts. Infants enrolled in administrative services only plans were excluded because access to medical records was not allowed for patients in these plans. The final study population consisted only of infants for whom Optum could seek medical charts