atrial fibrillation and weight loss

a 5-year study from Australia (the LEGACY study, Long-term Effect of Goal directed weight management on Atrial fibrillation Cohort) looked at a cohort of people with atrial fibrillation (paroxysmal or persistent) to assess the relationship between weight loss, weight fluctuations and atrial fibrillation (see afib and weight loss JACC 2015 in dropbox, or doi.org/10.1016/j.jacc.2015.03.002). details:

--355 patients with atrial fibrillation (AF) and BMI≥ 27 kg/m2 (mean age 65, 64% male, weight 100 kg, BMI 33, 53% with paroxysmal AF, 80% hypertensive, 30% diabetic, 30% drinking >30g alcohol/week) were offered weight management

        ​--face-to-face counseling, with 3-monthly evaluation. meals were high protein/low glycemic index and calorie-controlled.  if patient lost <3% of weight after 3 months, they received very-low-calorie meal replacement sachets for 1-2 meals/day. also, there was an exercise component, increasing to 300 min of moderate-intensity activity/week.

--AF management was independent of this weight loss study, with rate and rhythm control strategies per the physicians there (rhythm control mostly by flecainide or sotolol). ablation was used if patients remained symptomatic

--AF was determined at least annually by clinical review, 12-lead EKG, and 7-day Holter monitoring

--AFSS (AF Severity Scale) was used to monitor the clinical burden of AF (this scale assesses the frequency, duration, and clinical severity of AF). and the 7-day Holter assessed the freedom from AF

--weight loss was categorized as ≥ 10% (group 1, with 135 patients and mean wt loss of 16 kg), 3-9% (group 2, with 103 patients and mean wt loss of 6 kg), and <3% (group 3, with 117 patients, and mean wt gain of 2 kg). no difference in baseline characteristics or follow-up among these groups

--of note, for those with ≥​ 10 kg wt loss, the loss was pretty durable: 66% who lost his amount in the first year maintained it at 34.5 months. This was likely because 85% of them continued attending the weight management clinics.

results:

        --weight loss was associated with changes in cardiac risk factors (all findings were significant, and almost all at p<0.001 level):

                ​--systolic blood pressure, from baseline of around 145, decreased 18 mmHg in group 1, 10 mmHg in group 2 and 7 mmHg in group 3 (p<0.001) -- despite decreasing blood pressure meds in group 1 and increasing them in group 3.

                --lipids: for groups 1, 2, and 3 -- from baseline of around 110, decreased 37, 23 and increased 4 mg/dL; HDL increased 8, 4, and 4 mg/dL

                --hsCRP: for groups 1, 2, and 3 -- from baseline of around 5, decreased 3.9, 1.7, and increased 0.8 mg/dL

                ​--echo findings: for groups 1, 2, and 3 -- LA volume from baseline of around 38, decreased  6.7, 4.8, and and increased 1.4 ml/m²; IV septum from baseline of around 11.5, decreased  1.6, 0.6, and 0.1 mm; E/E' ratio from baseline of around 13 decreased 4.3, 2.8 and increased                             2.1.

                ​--all clinical scores measured (AF frequency, duration, episode severity, symptom subscale and global well-being) were dramatically better in groups 1 vs 2 vs 3

        --at final followup: for groups 1, 2, and 3 -- 45.5%, 22.2% and 13.4% remained free from arrhythmia without antiarrhythmic drugs or ablation (p<0.001), with group 1 having a 6-fold greater probability of arrhythmia-free survival than the other 2 groups.

        --on multivariate analysis: predictors of AF recurrence were group 2 vs group 1 [HR:3.0 (1.4-2.9)] and group 3 vs group 1 [HR 3.0 (2.0-4.3)], both p<0.001. also, echo IV septum thickness and E/E' ratio were independent predictors, as well as a history of diabetes.

        --arrhythmia-free survival with and without rhythm control strategies was greatest in group 1 (p<0.001, comparing to group 2 or 3): 86.2% in group 1, 65.5% in group 2, and 39.6% in group 3

        --weight fluctuation of >5% partially offset this benefit (2-fold increased risk of arrhythmia recurrence)

so, what does this mean?? 

    --this is the best study I've seen showing that weight loss is helpful in the treatment of AF. I did send out a blog 2 years ago of a short-term trial from Australia by this same group which showed efficacy of weight loss, including echocardiographic changes (see http://gmodestmedblogs.blogspot.com/2013/12/atrial-fibrillation-and-weight-reduction.html  ). but the current study is long-term and found really profound differences in cardiac risk factors, structural changes in the heart and both AF control and recurrences, and AF symptoms and general well-being.  these changes raise the untested possibility of stopping anticoagulation in those no longer with AF, with the associated personal benefits to patients (anticoagulation management, adverse effects of drugs, medicalization) and costs to the system.

    ​--this study also reinforces how hard it is to achieve the weight loss. They had a long-term study (with up to 5 years of followup), finding that the group that consistently lost weight and maintained the weight loss had regular prolonged involvement in weight management clinics. In this group, there were sustained changes in many cardiac risk factors as well as AF, and it certainly seems to me that instituting and supporting long-term weight management clinics is not only potentially beneficial to the individuals involved and in many ways (medical, psychological, general functioning) but also very cost-effective.

    --of interest, NPR just had a segment on exercise in Finland (see http://www.npr.org/sections/health-shots/2015/07/28/426748088/how-finns-make-sports-part-of-everyday-life​ ), finding that exercise there is treated as a right (government subsidies, integration into workday including paid time to workout during the week, extensive bike and walking trail systems), is associated with better work performance (more workforce cohesion/loyalty) and decreasing health care costs in a more physically active workforce (the Finnish minister of health estimates a $5.5 billion cost savings by people riding their bike to work, which now happens with 1/2 of the male and 1/3 of female employees).