Screening strategies for gestational diabetes mellitus at the Aga Khan University Hospital, Nairobi: a cross sectional study

Background: Universal screening strategy for gestational diabetes mellitus offers biochemical screening to all women irrespective of risk factor status while selective strategy screens only those with risk factors. The Aga Khan University Hospital adopted a selective screening protocol by consensus. This study compares both strategies and the prevalence of risk factors for gestational diabetes. Objectives: To compare screening strategies for gestational diabetes mellitus and determine the risk factors associated with gestational diabetes mellitus at The Aga Khan University Hospital, Nairobi. Methods: A cross-sectional study of 185 participants recruited at ≤ 28 weeks of pregnancy at Aga Khan University Hospital, Nairobi. All had risk factor assessment, a two-step screening with 50 g 1 hour glucose challenge test then a 2 hour 75 g OGTT for those with abnormal 50g 1 hour challenge test. Results: Prevalence of an abnormal screening test in a group with risk factors was 12.0% (95% CI: 6.0% to 17.9%) and in the group without risk factors it was 19.1% (95% CI: 9.5% to 28.7%). GDM prevalence was 1.08% and impaired glucose tolerance 8.65%. Obesity was the commonest risk factor (35.7% with BMI > 30). The data suggests negative correlations though not statistically significant for fasting glucose levels (Pearson correlation coefficient, r = -0.06, p-value = 0.42) and one hour post glucose load (Pearson correlation coefficient, r = -0.11, p-value = 0.58) with BMI. A positive correlation between BMI and blood glucose levels at 2 hours was also not statistically significant (Pearson correlation coefficient, r = 0.07, p-value = 0.36). Conclusion: There was no evidence of a difference between the screening strategies. Obesity was the commonest risk factor in the screened population. There was no significant positive correlation of BMI to measured fasting, 1hr and 2hour glucose levels. This defies known expectations and may be a subject for future research.