Variation in effectiveness of the NHS Diabetes Prevention Programme in people diagnosed with non-diabetic hyperglycaemia by age, sex, BMI, and deprivation: A matched cohort analysis of 69,801 people

AIMS: The NHS Diabetes Prevention Programme (DPP) is a behaviour-change programme aimed at adults diagnosed with non-diabetic hyperglycaemia (NDH), who are at higher risk of developing type 2 diabetes mellitus (Diabetes). This paper explores the heterogeneity in the effectiveness of the DPP by age, sex, BMI, and practice location deprivation (IMD).

METHODS: Matched cohort analysis with random-effects parametric survival models, evaluating the association between referral to the DPP and conversion to diabetes, with interactions fitted for age, sex, BMI, and IMD.

RESULTS: 18,470 patients referred to the programme were matched to 51,331 controls. None of the interactions of patient characteristics with referrals were statistically significant. For women, the difference in the HR of conversion to diabetes, compared to men, was HR = 0.94 (95% CI: 0.81, 1.08, p = 0.38); For those aged [18-34], HR = 0.79 (95% CI: 0.34, 1.84, p = 0.58) and aged [75-84] HR = 0.86 (95% CI:0.66, 1.12, p = 0.26) compared to those aged [55-64]. The HR for conversion was 0.88 (95% CI:0.62, 1.26, p = 0.49) for those with a BMI ≥ (25-29.9) kg/m 2 and HR = 0.76 (95% CI:0.54, 1.06, p = 0.10) in those with a BMI ≥ 30 kg/m 2 compared to BMI < 25 kg/m 2. Finally, for the most deprived IMD quintile, compared to the least deprived, the difference in the conversion was HR = 1.31 (95% CI: 0.98, 1.73, p = 0.06).

CONCLUSIONS: The DPP was effective in reducing conversion rates from NDH to diabetes as shown in our previous study results. The intervention appeared to be similarly effective by age, sex, BMI, and deprivation.