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.
Bibliographical noteFunding Information:
Steering Committee: Jonathan Ainsworth, Jane Anderson, Abdel Babiker, David Chadwick, Valerie Delpech, David Dunn, Martin Fisher, Brian Gazzard, Richard Gilson, Mark Gompels, Phillip Hay, Teresa Hill, Margaret Johnson, Stephen Kegg, Clifford Leen, Mark Nelson, Chloe Orkin, Adrian Palfreeman, Andrew Phillips, Deenan Pillay, Frank Post, Caroline Sabin (PI), Memory Sachikonye, Achim Schwenk, John Walsh. Central Co-ordination: UCL Research Department of Infection & Population Health, Royal Free Campus, London (Teresa Hill, Susie Huntington, Sophie Josie, Andrew Phillips, Caroline Sabin, Alicia Thornton); Medical Research Council Clinical Trials Unit (MRC CTU), London (David Dunn, Adam Glabay). Participating Centres: Barts and The London NHS Trust, London (C Orkin, N Garrett, J Lynch, J Hand, C de Souza); Brighton and Sussex University Hospitals NHS Trust (M Fisher, N Perry, S Tilbury, D Churchill); Chelsea and Westminster Hospital NHS Trust, London (B Gazzard, M Nelson, M Waxman, D Asboe, S Mandalia); Health Protection Agency – Centre for Infections London (HPA) (V Delpech); Homerton University Hospital NHS Trust, London (J Anderson, S Munshi); King’s College Hospital NHS Foundation Trust, London (H Korat, J Welch, M Poulton, C MacDonald, Z Gleisner, L Campbell); Mortimer Market Centre, London (R Gilson, N Brima, I Williams); North Middlesex University Hospital NHS Trust, London (A Schwenk, J Ainsworth, C Wood, S Miller); Royal Free NHS Trust and UCL Medical School, London (M Johnson, M Youle, F Lampe, C Smith, H Grabowska, C Chaloner, D Puradiredja); St. Mary’s Hospital, London (J Walsh, J Weber, F Ramzan, N Mackie, A Winston); The Lothian University Hospitals NHS Trust, Edinburgh (C Leen, A Wilson); North Bristol NHS Trust (M Gompels, S Allan); University of Leicester NHS Trust (A Palfreeman, A Moore); South Tees Hospitals NHS Foundation Trust (D Chadwick, K Wakeman). NSHPC: We gratefully acknowledge the contribution of the midwives, obstetricians, genitourinary physicians, paediatricians, clinical nurse specialists and all other colleagues who report to the NSHPC through the British Paediatric Surveillance Unit of the Royal College of Paediatrics and Child Health, and the obstetric reporting scheme run under the auspices of the Royal College of Obstetricians and Gynaecologists. We thank Janet Masters who co-ordinates the study and manages the data and Icina Shakes for administrative support. Ethics approval for NSHPC was renewed following review by the London Multi-Centre Research Ethics Committee in 2004 (MREC/04/2/009). UK CHIC is funded by the Medical Research Council (MRC), UK (grants G00001999 and G0600337). NSHPC receives core funding from the Health Protection Agency (grant number GHP/003/013/003). Data is collated at the UCL Institute of Child Health which receives a proportion of funding from the Department of Health’s National Institute for Health Research Biomedical Research Centres funding scheme. Susie Huntington has a UCL Studentship, funded by the MRC, for postgraduate work. Claire Thorne holds a Wellcome Trust Research Career Development Fellowship.
- Antiretroviral therapy
- Cohort analysis
- Data linkage
- Pregnant women
- United Kingdom