Of 65 practices agreeing to participate in the Counterweight Programme, 56 participated. Nine practices did not enrol patients due to nurses leaving their positions, maternity leave, and competing practice priorities. In the 56 practices, activity patterns varied: 34 practices were continuing to enrol new patients into the programme 12 months after the programme had started; 10 practices enrolled ≥60 patients over 12 months; 17 practices enrolled ≥40 patients over 12 months; and the remaining 29 practices enrolled <40 patients over 12 months. Twenty-two practices from deprived areas, 22 from intermediately-deprived areas, and 12 practices from affluent areas contributed 36.4%, 29.5%, and 34.2% of patients respectively.
The 56 practices identified 2095 patients, of which 1906 satisfied eligibility criteria. At data-set closure, 1419 patients had reached ≥12 months, and 825 had reached 24 months. Data were available for 642 of 1419 patients at 12 months, and for 357 of 825 at 24 months; the remainder did not reach these data-collection time-points. Baseline data are presented for all 1906 enrolled patients, together with results at 3, 6, 12, and 24 months. As some patients missed one or more appointments or dropped out, mean weight changes reflect a patient sub-group of those who attended, comprising different individuals at different time-points.
Mean age for 1906 patients at baseline was 49.4 years (SD 13.5 years, range 18.1–76.0 years); 77% were female; and, of those enrolled in the programme, obesity was severe (mean weight 101.1 kg, BMI 37.1 kg/m2). Nearly three-quarters of patients had ≥1, nearly half ≥2, and over a quarter ≥3 obesity-related comorbidities ().
Weight changes at 12 months ranged from +17.5 kg to −34.9 kg. Of patients attending at 12 months (n = 642), mean weight change was approximately −3.0 kg (95% CI = −3.5 to −2.4; ). Mean change in BMI at 12 months was −1.1 kg/m2 (95% CI = −1.3 to −0.9), with 30.7% of 12-month attenders (13.9% of all patients) maintaining ≥5% weight loss ( and ). Of patients attending at 24 months, mean weight change was −2.3 kg (95% CI = −3.2 to 1.4, n = 357/825) with 31.9% of 24-month attenders (13.8% of all 825 patients) known to have lost ≥5% of their initial weight.
Change in weight and body mass index (BMI) from baseline in 1419 patients enrolled for at least 12 months.
Data from attenders at the 12-month time-point, as a proportion of attenders and as a proportion of all 1419 patients who had been enrolled for at least 12 months, who had lost ≥5% of their initial weight.
A further 119 patients who missed the 12-month time-point returned at 24 months when they had a mean weight change of −1.4 kg. Patients known to remain in Counterweight for ≥12 months (642 + 119 = 761) accounted for 54% of 1419 enrolled.
Weight change data reflect outcomes from a variety of specific treatments.17
Seventy per cent of patients attending at 12 months received individual lifestyle interventions (prescribed eating plan or goal setting), 34% attended a group intervention (some patients had individual and group intervention), and 19% received anti-obesity drugs at some point. Some patients received a combination of interventions at the same time. Patients attending session 6 of the intervention programme received specific weight loss maintenance advice; 13% of those attending at 12 months were recorded as having received specific weight-loss maintenance advice as well as weight-loss advice.
Factors associated with weight change
Some factors were associated with greater mean weight loss at 12 months (). Males lost an average of 3.4 kg whereas females lost an average of 2.8 kg. Their 95% Cls overlap, suggesting that the observed difference did not reach statistical significance. The number of visits for Counterweight appeared to be associated with greater mean weight loss. Ages 35–44 years, higher baseline BMI, and absence of diabetes or arthritis were also associated with increased mean weight loss ().
Factors affecting weight loss in patients who attended for data collection at 12 months (n = 642).a
Mean secondary endpoint changes in all patients with 12-month data were: total-cholesterol −0.29 mmol/L (n = 303, P < 0.001); low-density lipoprotein cholesterol −0.35 mmol/L (n = 172, P < 0.001); HDL-cholesterol +0.03 mmol/L (n = 234, P = 0.08); systolic blood pressure −2.03 mmHg (n = 580, P = 0.01); diastolic blood pressure −1.15 mmHg (n = 580, P = 0.01), and (in patients with diabetes only) HbA1c −0.19% (n = 93, P = 0.17); and fasting glucose +0.08 mmol/L (n = 28, non-significant).