Validation of spontaneous abortion diagnoses in the Danish National Registry of Patients

Abstract

PurposeThe purpose of this study is to validate the diagnosis of spontaneous abortion (SA) recorded in the Danish National Registry of Patients (DNRP).MethodsWe randomly selected patients registered in the DNRP with a diagnosis of SA between 1980 and 2008 from hospitals in the county of North Jutland and searched for their discharge records in hospital files. We estimated positive predictive value (PPV) of the DNRP diagnosis and stratified the analysis by period (1980–1994 versus 1995–2008), hospital type (regional versus local), and International Classification of Diseases revisions (ICD-8 versus ICD-10).ResultsWe could identify hospital files of 117/174 (67%) sampled registration records. Of those, the diagnosis was confirmed in 114 patients, yielding a PPV of 97.4% (95% confidence interval = 92.7%–99.5%). The PPV did not markedly vary by period, hospital type, or ICD revision. Among the three patients with available data who did not fulfill the criteria for SA, one had an induced abortion and two had threatened abortion but did not miscarry.ConclusionRegistration of SA in the DNRP accurately reflects the diagnoses recorded in medical charts. The DNRP is a suitable source of data on SAs for epidemiologic research.

Metoclopramide in Pregnancy and Risk of Major Congenital Malformations and Fetal Death

“…19 Cases of stillbirth (fetal loss after 22 completed weeks), preterm birth (delivery before 37 completed weeks), low birth weight (<2500 g), and SGA (lowest 10th percentile of the gestational agespecific birth weight in the cohort) were identified from the Medical Birth Register.…”

Hyperemesis, gestational hypertensive disorders, pregnancy losses and risk of autoimmune diseases in a Danish population-based cohort

“…However, for the remaining ADs no systematic validation effort has been undertaken. While records of stillbirths, and induced abortions in Danish registers are believed to be close to 100% valid and complete, formal validation of the other pregnancy variables has been undertaken only for preeclampsia and spontaneous abortions, reporting that these records are of sufficiently good quality for epidemiologic research [51,52]. The decision to treat and to hospitalize a patient with a complicated pregnancy may be influenced by a number of individual factors in addition to those related to the severity of symptoms and clinical signs, such as a person's threshold for reporting pregnancy problems and the patient's health seeking behavior.…”

Pregnancy Loss and Later Risk of Atherosclerotic Disease

“…8,9 The completeness of registration and validity of spontaneous abortion, myocardial infarction, and cerebral infarction diagnoses are excellent, minimizing the likelihood of misclassification. 10,11,13 Furthermore, we used a conservative algorithm to identify miscarriages and excluded all miscarriages with coregistration of molar pregnancy, induced abortion, and extrauterine pregnancy. Unfortunately, information on timing of miscarriage (in gestational weeks) was not available, making it impossible to examine early and late miscarriages separately.…”

“…12 From 1977 onward, parts of the register have been based on the National Patient Register, in which the positive predictive value of a spontaneous abortion diagnosis is 97%. 13 The National Diabetes Register is based on hospital diabetes mellitus diagnoses, filled prescriptions for diabetes mellitus treatment, primary care measurements of blood glucose, and diabetic chiropody. The register contains nationwide information on diabetes mellitus diagnoses from 1991 onward.…”