Validating inflammatory bowel disease (IBD) in the Swedish National Patient Register and the Swedish Quality Register for IBD (SWIBREG).

BACKGROUND: Both the Swedish National Patient Register (NPR) and the Swedish Quality Register for inflammatory bowel disease (IBD, SWIBREG) are important sources of research data and information. However, the validity of a diagnosis of IBD in these registers is unknown. METHODS: Medical charts of 129 randomly selected patients from the NPR and 165 patients registered both in SWIBREG and the NPR were reviewed. Patients were classified according to standardized criteria for ulcerative colitis (UC), Crohn's disease (CD), or IBD unclassified (IBD-U). Positive predictive values (PPVs) for UC, CD, IBD-U (only SWIBREG), or having any form of IBD were then calculated. RESULTS: For cases with ≥2 diagnoses of IBD in the NPR (hospitalizations or non-primary care outpatient visits), the PPV was 93% (95% CI: 87-97) for any IBD, 79% (66-88) for UC and 72% (60-82) for CD. In UC patients with ≥2 UC diagnoses but never a CD diagnosis, the PPV increased to 90% (77-97). The PPV for CD in patients with ≥2 CD diagnoses but never a UC diagnosis was 81% (67-91)). Combining data from SWIBREG (≥1 record) and the NPR (≥1 record), the PPV was 99% for any IBD (97-100), 96% (89-99) for UC, and 90% (82-96) for CD. CONCLUSION: The validity of the UC, CD, and IBD diagnoses is high in the NPR but even higher when cases were identified both in SWIBREG and the NPR. These results underline the need for a well-functioning Swedish Quality Register for IBD as a complement to the NPR.

Pregnancy outcomes in patients with ankylosing spondylitis: a nationwide register study.

INTRODUCTION: Unlike other chronic inflammatory diseases, little is known about how ankylosing spondylitis (AS) affects outcomes of pregnancy and birth characteristics. METHODS: In a nationwide population-based case-control study, 388 deliveries among women with AS (identified in the Swedish National Patient Register and Medical Birth Register) and deliveries among matched controls (n=1082) from the general population were included. Information regarding pregnancies after AS diagnosis, birth outcomes and possible confounders were retrieved from the national Swedish registers. ORs with 95% CIs were calculated with generalised estimating equations. RESULTS: Emergency and elective Caesarean section (CS) were performed in 16.5% and 9.8% of deliveries among women with AS compared with 6.5% and 6.9%, respectively, in population controls, resulting in OR of 3.00 (95% CI 2.01 to 4.46) and 1.66 (95% CI 1.09 to 2.54), respectively. Offspring of women with AS were more often preterm (9.0% vs 4.9%) and small-for-gestational-age (SGA) (3.1% vs 1.5%), resulting in an OR of 1.92 (95% CI 1.17 to 3.15) and 2.12 (95% CI 1.00 to 4.50), respectively. Adjustment for smoking habits, age, educational level, parity and exclusion of women with comorbidities resulted in similar or only slightly lower point estimates of risk. Cases with a more extensive antirheumatic therapy exposures tended to have a higher risk for elective CS and being SGA. CONCLUSIONS: Women with AS had a higher prevalence for several adverse birth outcomes, with results suggesting an influence by both disease severity and comorbidities.