Insights from a general practice service evaluation supporting a lower carbohydrate diet in patients with type 2 diabetes mellitus and prediabetes: a secondary analysis of routine clinic data including HbA1c, weight and prescribing over 6 years

Abstract

BackgroundIn a single general practice (GP) surgery in England, there was an eightfold increase in the prevalence of type 2 diabetes (T2D) in three decades with 57 cases and 472 cases recorded in 1987 and 2018, respectively. This mirrors the growing burden of T2D on the health of populations round the world along with healthcare funding and provision more broadly. Emerging evidence suggests beneficial effects of carbohydrate-restricted diets on glycaemic control in T2D, but its impact in a ‘real-world’ primary care setting has not been fully evaluated.MethodsAdvice on a lower carbohydrate diet was offered routinely to patients with newly diagnosed and pre-existing T2D or prediabetes between 2013 and 2019, in the Norwood GP practice with 9800 patients. Conventional ‘one-to-one’ GP consultations were used, supplemented by group consultations, to help patients better understand the glycaemic consequences of their dietary choices with a particular focus on sugar, carbohydrates and foods with a higher Glycaemic Index. Those interested were computer coded for ongoing audit to compare ‘baseline’ with ‘latest follow-up’ for relevant parameters.ResultsBy 2019, 128 (27%) of the practice population with T2D and 71 people with prediabetes had opted to follow a lower carbohydrate diet for a mean duration of 23 months. For patients with T2D, the median (IQR) weight dropped from of 99.7 (86.2, 109.3) kg to 91.4 (79, 101.1) kg, p<0.001, while the median (IQR) HbA1c dropped from 65.5 (55, 82) mmol/mol to 48 (43, 55) mmol/mol, p<0.001. For patients with prediabetes, the median (IQR) HbA1c dropped from 44 (43, 45) mmol/mol to 39 (38, 41) mmol/mol, p<0.001. Drug-free T2D remission occurred in 46% of participants. In patients with prediabetes, 93% attained a normal HbA1c. Since 2015, there has been a relative reduction in practice prescribing of drugs for diabetes leading to a T2D prescribing budget £50 885 per year less than average for the area.ConclusionsThis approach to lower carbohydrate dietary advice for patients with T2D and prediabetes was incorporated successfully into routine primary care over 6 years. There were statistically significant improvements in both groups for weight, HbA1c, lipid profiles and blood pressure as well as significant drug budget savings. These results suggest a need for more empirical research on the effects of lower carbohydrate diet and long-term glycaemic control while recording collateral impacts to other metabolic health outcomes.

Nutritional Approaches for the Management of Nonalcoholic Fatty Liver Disease: An Evidence-Based Review

“…An important point to consider for LCD is that it has shown effectiveness for reducing body weight, HbA1c, serum lipids, and blood pressure in patients with T2DM and prediabetes after six years of treatment. Of course, these results show a clinical applicability in situations of chronic metabolic alterations [ 47 ].…”

Weight loss, hypertension and mental well-being improvements during COVID-19 with a multicomponent health promotion programme on Zoom: a service evaluation in primary care

“…8 However, evidence indicates that carbohydrate restriction is also effective both via digital applications and in primary care and community settings to address excess weight, cardiometabolic risk and glycaemic control. [9][10][11][12][13][14][15] One proposed mechanism for the effectiveness of carbohydrate restriction for weight loss is that it reduces insulin secretion, reducing its anabolic, fat-storing effects and therefore facilitating oxidation of fatty acids from adipose tissue. 16 Furthermore, because insulin stimulates glucose uptake, suppresses fatty acid oxidation and promotes fat and glycogen deposition, hyperinsulinaemia effectively removes metabolic fuels from the circulation, potentially driving hunger and overeating.…”

“…29 31-33 The long-term sustainability and safety of carbohydrate restriction is debated, 34 although a recent primary care service evaluation reported successful compliance with concomitant weight and cardiometabolic improvements over 6 years. 15 In 2020 in the UK, COVID-19 restrictions disrupted opportunities in primary care for brief interventions to address excess weight and referral to weight management services. Face-to-face community-based interventions were not possible, although some commercial services were delivered remotely.…”

“… 29 31–33 The long-term sustainability and safety of carbohydrate restriction is debated, 34 although a recent primary care service evaluation reported successful compliance with concomitant weight and cardiometabolic improvements over 6 years. 15 …”

Supporting people to implement a reduced carbohydrate diet: a qualitative study in family practice

“…20 21 In the UK, interest in low-carb among HCPs has been spurred by influential general practitioner (GP), David Unwin, 22 who has observed improvements in patients' metabolic markers in individual case reports and retrospective analyses within his family practice. 23 Qualitative research is important for investigating the dynamics of food-related healthcare interventionswhich can be characterised as 'complex interventions' 24 due to their multiple elements and potential mechanisms of action. It is crucial to understand how such complex dietary interventions are undertaken, what they involve, how and why they work and for whom.…”