Does one size really fit all? Only by considering individual preferences and priorities will the true impact of insulin pump therapy on quality of life be determined

Barnard and colleagues [1] report a systematic review outlining the effects of continuous subcutaneous insulin infusion (CSII) pump therapy on quality of life (QoL). This review is the first to draw together evidence from 17 studies conducted over the past 20 years to consider the question of whether insulin pump therapy can improve QoL. At face value, the evidence seems to suggest that there are few demonstrable benefits of pump therapy for QoL. In nine studies, insufficient data were presented to determine effect size. For seven of the remaining eight studies, several measurements were used, most showing very small (arguably trivial) effect sizes. In only one study [incidentally, the first and larger ( n = 183) than all those that have followed], was a large effect reported [2]. In this study, those ‘who chose CSII and remained on this treatment for 1 year reported greater improvements in treatment satisfaction’ [2, p. 238]. As pointed out in the review, interpretation of studies of pump therapy has often been limited by study design, sample size, or sample selection. In 12 of the 17 studies, one or more of the following limitations was noted: no control group, no controlling for confounding variables, and/or comparison groups which were not truly comparable. In many cases, poor study design was a factor, with those receiving insulin pump therapy also receiving greater diabetes education and increased contact time with health-care professionals. Even the most robust designs, comprising the five randomized controlled trials (RCTs), can be criticized for not taking account of individual preferences [3]. With an intervention such as an insulin pump, patient preference (which will influence motivation, determination and willingness to continue with treatment) is absolutely critical to success; a factor alluded to in the conclusions drawn by Lewis et al . [2]. In a recent audit of consecutive patients fulfilling National Institute for Clinical Excellence (NICE) criteria and making an informed decision to commence CSII within the Newcastle clinical service, safe and effective management with improved HbA 1c without further severe hypoglycaemia was observed in 80% at 6 months, all of whom wished to remain on pump therapy [4]. In a 6-month prospective pilot study undertaken at the same centre in which patients were randomized to CSII, recurrent severe hypoglycaemia was prevented in 71% with mean HbA 1c reduction of 1.1%, but 57% elected to stop pump therapy at the end of the study [5]. Lack of patient choice regarding allocated intervention, inherent in the conventional RCT design, may well have contributed to this. Potential benefits for QoL (such as increased flexibility, independence, and dietary freedom) can be outweighed by the additional burdens of pump therapy (including need for frequent daily self monitoring of blood glucose, continual physical attachment to a device, and perceived restrictions to activities such as swimming and sexual intimacy). While some people may view insulin pump therapy as the gold standard for optimal self management of their diabetes, for others, being attached to an insulin pump would be akin to a life sentence. In the words of Carl Jung: ‘the shoe that fits one person pinches another; there is no recipe for living that suits all cases’. To quote one individual in the Newcastle clinical programme asked to comment after 6 months using CSII therapy: ‘the insulin pump is tremendous, every diabetic should have one! The quality of life and good health is excellent. ’ Another, at the end of the RCT, described the pump as ‘like wearing handcuffs’. One of the most fundamental issues with studies such as those described in the review of Barnard et al . [1] is that none appear to have fully considered the question ‘what is QoL? ’ before they set about measuring it. The authors of the review can be commended for adopting a specific definition of QoL for their analysis: