Study of long-acting reversible contraceptive use in a UK primary care database: validation of methodology

Feasibility study to identify women of childbearing age at risk of pregnancy not using any contraception in The Health Improvement Network (THIN) database

Background

Worldwide the rate of unplanned pregnancies is more than 40%. Identifying women at risk of pregnancy can help prevent negative outcomes and also reduce healthcare costs of potential complications. It can also allow the investigation of the natural history of pregnancy outcomes, such as ectopic pregnancies or miscarriages. The use of medical records databases has been a crucial development in the field of pharmacoepidemiology – e.g. The Health Improvement Network (THIN) database is a validated database representative of the UK population. This project aimed to test the feasibility of identifying a population of women of childbearing age who are at risk of pregnancy not using any contraception in THIN database.

Methods

First a cohort of women of childbearing age (15-45yo) was identified. By applying a computer-based algorithm, containing codes for contraception methods or other suggestion of contraception, the risk of pregnancy was then ascertained. Next, two validation steps were implemented: 1) Revision of medical records/free text and 2) Questionnaires were sent to primary care practitioners (PCP) of women whose medical records had been reviewed. Positive predicted values (PPV) were calculated.

Results

A total of 266,433 women were identified in THIN. For the first validation step, 123 records were reviewed, with a PPV of 99.2% (95%CI: 95.5–99.9). For the questionnaires step, the PPV was of 82.3% (95%CI: 70–91.1). Information on sexual behaviour and attitudes towards conception was not captured by THIN.

Conclusion

This study shows that by applying a comprehensive computer-based algorithm, THIN can be used to identify women at risk of pregnancy.

Provider and Health System Factors Associated with Usage of Long-Acting Reversible Contraception in Adolescents

STUDY OBJECTIVE

Long-acting reversible contraception (LARC) is recommended as first-line contraception for adolescents. Surveys of primary care providers suggest that physician and clinic factors might influence LARC counseling, but their effect on usage is unknown. Our objective was to explore provider and clinic characteristics associated with LARC usage in adolescents. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: We conducted a cross-sectional study of 5363 women ages 15-21 years receiving primary care within a large health system in Massachusetts in 2015. We used data abstracted from electronic medical records to characterize rates of LARC usage. We analyzed the association of provider (specialty, degree, gender, resident status, LARC credentialing) and clinic (Title X funding, onsite LARC provision, onsite obstetrician-gynecologist) factors with adolescents' LARC usage using multivariate logistic regression.

RESULTS

Overall, 3.4% (95% confidence interval [CI], 2.9-3.9) of adolescents were documented as currently using a LARC method. Older adolescents were significantly more likely to use a LARC method (adjusted odds ratio, 2.41; 95% CI, 1.62-3.58 for women ages 20-21 years compared with ages 15-17 years). Adolescents whose primary care provider was a resident were significantly more likely to use a LARC method (adjusted odds ratio, 1.65; 95% CI, 1.02-2.68). Provider specialty, degree, gender, onsite LARC provision, and onsite obstetrician-gynecologist were not significantly associated with LARC usage in adolescents.

CONCLUSION

Being older and having a primary care provider early in their training increased the odds of LARC usage among adolescents in a large Massachusetts health system. Across primary care specialties, educating providers about the appropriate uses of LARC methods in nulliparous adolescents might facilitate LARC usage.

Prescribing of cyproterone acetate/ethinylestradiol in UK general practice: a retrospective descriptive study using The Health Improvement Network

OBJECTIVE

To investigate prescribing patterns of cyproterone acetate/ethinylestradiol (CPA/EE) in the United Kingdom before and after the 2013 prescribing guidance.

STUDY DESIGN

We conducted a retrospective descriptive study in UK general practice. The study population included women with a first prescription (index date) for CPA/EE in The Health Improvement Network in 2011 (N=2760), 2012 (N=2923) and 2014 (N=2341). We evaluated the proportion of new CPA/EE users with (i) a diagnosis of a hyperandrogenic condition, menstrual problem, consultation for contraception management, and other acne treatment, in the year before the index date; and (ii) proportion of new CPA/EE users with concomitant use of another hormonal contraceptive (HC).

RESULTS

The percentage of CPA/EE new users with a record of a hyperandrogenic condition was 61% in 2011, 62% in 2012 and 63% in 2014. Corresponding percentages for acne were 51%, 54% and 55%, respectively. When manually reviewing patient records for a sample of CPA/EE new users (n=200), the acne was recorded in 77% of women, hirsutism in 9.5% and polycystic ovary syndrome in 9.5%. Majority of CPA/EE users had a prior acne diagnosis and/or treatment, 76% (n=2091) in 2011, 79% (n=2296) in 2012 and 78% (n=1834) in 2014. Concomitant use of CPA/EE and another HC was rare, 1% of CPA/EE users in 2011 and fewer than 0.5% of CPA/EE users in both 2012 and 2014.

CONCLUSIONS

Before and after 2013, the majority of UK women starting treatment with CPA/EE had a condition in line with its approved indication and had received prior acne treatment as per guidance.