title: Using two on-going HIV studies to obtain clinical data from before, during and after pregnancy for HIV-positive women.
abstract: BACKGROUND
  The UK Collaborative HIV Cohort (UK CHIC) is an observational study that collates data on HIV-positive adults accessing HIV clinical care at (currently) 13 large clinics in the UK but does not collect pregnancy specific data. The National Study of HIV in Pregnancy and Childhood (NSHPC) collates data on HIV-positive women receiving antenatal care from every maternity unit in the UK and Ireland. Both studies collate pseudonymised data and neither dataset contains unique patient identifiers. A methodology was developed to find and match records for women reported to both studies thereby obtaining clinical and treatment data on pregnant HIV-positive women not available from either dataset alone.
  
  
  RESULTS
  Women in UK CHIC receiving HIV-clinical care in 1996-2009, were found in the NSHPC dataset by initially 'linking' records with identical date-of-birth, linked records were then accepted as a genuine 'match', if they had further matching fields including CD4 test date. In total, 2063 women were found in both datasets, representing 23.1% of HIV-positive women with a pregnancy in the UK (n = 8932). Clinical data was available in UK CHIC following most pregnancies (92.0%, 2471/2685 pregnancies starting before 2009). There was bias towards matching women with repeat pregnancies (35.9% (741/2063) of women found in both datasets had a repeat pregnancy compared to 21.9% (1502/6869) of women in NSHPC only) and matching women HIV diagnosed before their first reported pregnancy (54.8% (1131/2063) compared to 47.7% (3278/6869), respectively).
  
  
  CONCLUSIONS
  Through the use of demographic data and clinical dates, records from two independent studies were successfully matched, providing data not available from either study alone.
authors: Research Department of Infection & Population Health, University College London, Royal Free Campus, Rowland Hill Street, London, NW3 2PF, UK. susan.huntington.09@ucl.ac.uk
authors: Susie E
authors: SE
authors: Huntington
authors: Loveleen K
authors: LK
authors: Bansi
authors: Claire
authors: C
authors: Thorne
authors: Jane
authors: J
authors: Anderson
authors: Marie-Louise
authors: ML
authors: Newell
authors: Graham P
authors: GP
authors: Taylor
authors: Deenan
authors: D
authors: Pillay
authors: Teresa
authors: T
authors: Hill
authors: Pat A
authors: PA
authors: Tookey
authors: Caroline A
authors: CA
authors: Sabin
mesh_terms: D000293:Adolescent; D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D006679:HIV Seropositivity / Q000453:epidemiology; D006801:Humans; D007494:Ireland / Q000453:epidemiology; D008498:Medical Record Linkage; D010342:Patient Acceptance of Health Care; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D011256:Pregnancy Outcome; D006113:United Kingdom / Q000453:epidemiology; D016387:Women's Health; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents