ABSTRACT
BACKGROUND: Hypertensive disorders of pregnancy (HDP) are associated with increased risks for cardiovascular disease later in life. The HDP incidence is commonly assessed using diagnostic codes, which are not reliable; and typically are expressed per-pregnancy, which may underestimate the number of women with an HDP history after their reproductive years. OBJECTIVES: This study sought to determine the incidence of HDP expressed as both per-pregnancy and per-woman, and to establish their associations with future chronic conditions and multimorbidity, a measure of accelerated aging, in a population-based cohort study. METHODS: Using the Rochester Epidemiology Project medical record-linkage system, the authors identified residents of Olmsted County, Minnesota, who delivered between 1976 and 1982. The authors classified pregnancies into normotensive, gestational hypertension, pre-eclampsia, eclampsia, pre-eclampsia superimposed on chronic hypertension, and chronic hypertension using a validated electronic algorithm, and calculated the incidence of HDP both per-pregnancy and per-woman. The risk of chronic conditions between women with versus those without a history of HDP (age and parity 1:2 matched) was quantified using the hazard ratio and corresponding 95% confidence interval estimated from a Cox model. RESULTS: Among 9,862 pregnancies, we identified 719 (7.3%) with HDP and 324 (3.3%) with pre-eclampsia. The incidence of HDP and pre-eclampsia doubled when assessed on a per-woman basis: 15.3% (281 of 1,839) and 7.5% (138 of 1,839), respectively. Women with a history of HDP were at increased risk for subsequent diagnoses of stroke (hazard ratio [HR]: 2.27; 95% confidence interval [CI]: 1.37 to 3.76), coronary artery disease (HR: 1.89; 95% CI: 1.26 to 2.82), cardiac arrhythmias (HR: 1.62; 95% CI: 1.28 to 2.05), chronic kidney disease (HR: 2.41; 95% CI: 1.54 to 3.78), and multimorbidity (HR: 1.25; 95% CI: 1.15 to 1.35). CONCLUSIONS: The HDP population-based incidence expressed per-pregnancy underestimates the number of women affected by this condition during their reproductive years. A history of HDP confers significant increase in risks for future chronic conditions and multimorbidity.
Subject(s)
Hypertension, Pregnancy-Induced/epidemiology , Hypertension, Pregnancy-Induced/physiopathology , Adult , Cardiovascular Diseases/diagnosis , Cardiovascular Diseases/epidemiology , Cardiovascular Diseases/physiopathology , Cohort Studies , Comorbidity , Female , Follow-Up Studies , Humans , Hypertension, Pregnancy-Induced/diagnosis , Incidence , Kidney Diseases/diagnosis , Kidney Diseases/epidemiology , Kidney Diseases/physiopathology , Metabolic Diseases/diagnosis , Metabolic Diseases/epidemiology , Metabolic Diseases/physiopathology , Pregnancy , Risk Factors , Time Factors , Treatment Outcome , Young AdultABSTRACT
OBJECTIVES: To develop and validate criteria for the retrospective diagnoses of hypertensive disorders of pregnancy that would be amenable to the development of an electronic algorithm, and to compare the accuracy of diagnoses based on both the algorithm and diagnostic codes with the gold standard, of physician-made diagnoses based on a detailed review of medical records using accepted clinical criteria. PATIENTS AND METHODS: An algorithm for hypertensive disorders of pregnancy was developed by first defining a set of criteria for retrospective diagnoses, which included relevant clinical variables and diagnosis of hypertension that required blood pressure elevations in greater than 50% of readings ("the 50% rule"). The algorithm was validated using the Rochester Epidemiology Project (Rochester, Minnesota). A stratified random sample of pregnancies and deliveries between January 1, 1976, and December 31, 1982, with the algorithm-based diagnoses was generated for review and physician-made diagnoses (normotensive, gestational hypertension, and preeclampsia), which served as the gold standard; the targeted cohort size for analysis was 25 per diagnosis category according to the gold standard. Agreements between (1) algorithm-based diagnoses and (2) diagnostic codes and the gold standard were analyzed. RESULTS: Sensitivities of the algorithm for 25 normotensive pregnancies, 25 with gestational hypertension, and 25 with preeclampsia were 100%, 88%, and 100%, respectively, and specificities were 94%, 100%, and 100%, respectively. Diagnostic code sensitivities were 96% for normotensive pregnancies, 32% for gestational hypertension, and 96% for preeclampsia, and specificities were 78%, 96%, and 88%, respectively. CONCLUSION: The electronic diagnostic algorithm was highly sensitive and specific in identifying and classifying hypertensive disorders of pregnancy and was superior to diagnostic codes.
