OBJECTIVE: In their evaluation of the cost effectiveness of insulin glargine, NICE included an assumption that switching to insulin would result in decreased health utility (8%). This altered notably any resulting cost-utility ratios. The purpose of this study was to test this hypothesis. METHODS: The design was a before-and-after study for type-2 patients who required switching to insulin. All followed an algorithm to achieve fasting and post-prandial blood glucose targets. Outcome measures included a measure of utilit (EQ5Dindex) at baseline, three-months and six-months. This report was a preliminary analysis of the first 48 subjects, of which 32 had completed 12 weeks and 26 had completed the full 24-week study. RESULTS: Of the 26 subjects, 21 (81%) remained on glargine with or without OHAs, two required additional pre-meal boluses, and three required twice-daily pre-mixtures. The mean (SD) EQ5Dindex at baseline was 0.655 (0.275; n=24), at three-months 0.637 (0.333; ? vs. baseline NS) and at six-months 0.710 (0.319; ? vs. baseline NS). At three-months, six patients had worse utility and six better utility, while 12 reported no change. At six-months, four patients had worse utility after switching, and 11 had better utility, the remaining nine subjects reported no change. Over the six-months, mean BMI increased from 29.4 to 30.0 kg/m2 (n=23, p<0.001) and mean HbA1c decreased from 10.1% to 7.8% (n=23, p<0.001). Mean daily insulin dose at six-months was 61.6 units (range 24 to 178). CONCLUSIONS: This is a limited but important interim analysis. The hypothesis that switching to insulin–here insulin glargine – resulted in a notable decrease in utility (quality of life) was rejected, with a trend for a clinically meaningful improvement in utility. Economic evaluations should, therefore, exclude this assumption. This observation is not necessarily generalisable to all insulin regimens.