Journal Watch—March 2015

| March 1, 2015

A quick look at the noteworthy articles in bariatric and metabolic research

Bariatric surgery can lead to net cost savings to health care systems: results from a comprehensive european decision analytic model.
Borisenko O, Adam D, Funch-Jensen P, Ahmed AR, Zhang R, Colpan Z, Hedenbro J. Obes Surg. 2015 Feb 2. [Epub ahead of print]
Synopsis: The objective of the present study was to evaluate the cost-utility of bariatric surgery in a lifetime horizon from a Swedish health care payer perspective. A decision analytic model using the Markov process was developed covering cardiovascular diseases, type 2 diabetes, and surgical complications. Clinical effectiveness and safety were based on the literature and data from the Scandinavian Obesity Surgery Registry. Gastric bypass, sleeve gastrectomy, and gastric banding were included in the analysis. Cost data were obtained from Swedish sources.

Results were as follows: bariatric surgery was cost saving in comparison with conservative management. It also led to a substantial reduction in lifetime risk of events: from a 16 percent reduction in the risk of transient ischaemic attacks to a 62 percent reduction in the incidence of type 2 diabetes. Over a lifetime, surgery led to savings of <euro>8408 and generated an additional 0.8 years of life and 4.1 quality-adjusted life years (QALYs) per patient, which translates into gains of 32,390 quality-adjusted person-years and savings of 66 million euros for the cohort, operated in 2012. Analysis of the consequences of a 3-year delay in surgery provision showed that the overall lifetime cost of treatment may be increased in patients with diabetes or a body mass index >40 kg/m2. Delays in surgery may also lead to a loss of clinical benefits: up to 0.6 life years and 1.2 QALYs per patient over a lifetime.
The authors concluded that bariatric surgery, over a lifetime horizon, may lead to significant cost savings to health care systems in addition to the known clinical benefits.
PMID: 25639648

Effectiveness of lifestyle-based weight loss interventions for adults with type 2 diabetes: a systematic review and meta-analysis.
Terranova CO, Brakenridge CL, Lawler SP, Eakin EG, Reeves MM. Diabetes Obes Metab. 2014 Dec 19. [Epub ahead of print]
Synopsis: The authors sought to provide a systematic review and meta-analysis of recent evidence on the effectiveness of lifestyle-based weight loss interventions for adults with type 2 diabetes. A search of the literature from January 2003 to July 2013 was conducted (PubMed, Embase, CINAHL and Web of Science). The studies considered eligible were randomized controlled trials evaluating weight loss interventions (diet and physical activity, with or without behavioural strategies) of ≥12 weeks duration, compared with usual care or another comparison intervention. Ten studies were included for review. Some heterogeneity was present in the sample, therefore, random-effects models were used to calculate pooled effects.

They found that intervention duration ranged from 16 weeks to 9 years, with all but one delivered via individual or group face-to-face sessions. From six studies comparing lifestyle intervention with usual care the pooled effect on weight (n = 5795) was -3.33kg [95% confidence interval (CI) -5.06, -1.60kg]), and on glycated haemoglobin (HbA1c; n=5784) was -0.29% (95% CI -0.61, 0.03%), with both attenuated in sensitivity analyses. The pooled within-group effect on weight (n=3063) from all 10 lifestyle intervention groups was -5.33kg (95% CI -7.33, -3.34kg), also attenuated in sensitivity analyses. None of the participant or intervention characteristics examined explained the heterogeneity. Only one study assessed whether intervention effects were maintained after the end of the intervention.
The authors concluded that lifestyle-based weight loss intervention trials in type 2 diabetes achieve, on average, modest reductions in weight and HbA1c levels, but results were heavily influenced by one trial. Evidence-based approaches for improving the effectiveness of lifestyle-based interventions in type 2 diabetes are needed, along with future studies reporting on maintenance and cost-effectiveness.
PMID: 25523815

Cost-effectiveness analysis of Qsymia for weight loss.
Finkelstein EA, Kruger E, Karnawat S. Pharmacoeconomics. 2014 Jul 2. [Epub ahead of print]
Synopsis: Phase 3 clinical trial results reveal that Qsymia is a clinically effective long-term treatment for obesity, but whether this treatment is cost-effective compared to a diet and lifestyle intervention has yet to be explored. Objective. To quantify the incremental cost-effectiveness of Qsymia (phentermine and topiramate extended-release) for health-related quality of life improvements. Study Design and Methods. Estimates are based on cost and quality of life outcomes from a 56-week, multicenter, placebo-controlled, phase 3 clinical trial undertaken in 93 health centers in the US. Participants were overweight and obese adults (aged 18–70 years) with a body-mass index of 27–45 kg/m2 and two or more comorbidities (hypertension, dyslipidemia, diabetes or pre-diabetes or abdominal obesity). The intervention was diet and lifestyle advice plus the recommended dose of Qsymia (phentermine 7.5mg plus topiramate 46.0mg) vs. control, which included diet and lifestyle advice plus placebo. The study was from the payer perspective. Costs included the prescription cost, medication cost offsets and physician appointment costs. Effectiveness was measured in terms of quality-adjusted life years gained (QALYs). The main outcome measure was incremental cost per QALY gained of the intervention relative to control. Results. Our base-case model, in which participants take Qsymia for 1 year with benefits linearly decaying over the subsequent 2 years, generates an incremental cost-effectiveness ratio (ICER) of $48,340 per QALY gained. Using the base-case assumptions, probabilistic sensitivity analyses reveal that the ICER is below $50,000 per QALY in 54 % of simulations. However, results are highly dependent on the extent to which benefits are maintained post medication cessation. If benefits persist for only 1 year post cessation, the ICER increases to $74,480. Conclusion. Although base-case results suggest that Qsymia is cost-effective, this result hinges on the time on Qsymia and the extent to which benefits are maintained post medication cessation. This should be an area of future research.
PMID: 24986038

Five-year medical and pharmacy costs after a medically supervised intensive treatment program for obesity.
Myers VH, McVay MA, Brashear MM,  et al. Am J Health Promot. 2014;28(6):364–371.
Synopsis: Purpose. The financial impact of intensive medical interventions for weight loss has not been fully studied. Design. A randomized pragmatic clinical trial. Setting. Seven primary care clinics and one research center in Louisiana. Subjects. Severely obese individuals (body mass index 40–60kg/m2) randomized to usual care (n = 190) or intensive medical management (n = 200). Forty-seven percent of participants completed year 2 follow-up and were included in the analyses. Intervention. Physician-monitored intervention with recommendations for 12 weeks of liquid diet followed by 4 months of group behavioral therapy, structured diet, and option of pharmacotherapy, and an additional 16 months of maintenance strategies. Measures. Two-year preintervention and 5-year postintervention measures were computed from claims data and included 1) medical costs excluding pharmacy, 2) pharmacy costs only, 3) total medical and pharmacy costs, and 4) medical and pharmacy subcategory costs. Analysis. Differential categories for preintervention and postintervention were created using total sample 75th percentiles. Chi-square tests were employed to compare the intervention groups both preintervention and postintervention with respect to the proportion of subjects above the 75th percentile for each of the cost categories. Results. Medical costs excluding pharmacy did not differ between groups. The intensive medical intervention group had a significantly smaller percentage of subjects above the 75th percentile for pharmacy costs only (p = .0125), and for antidiabetic agents (p = .0464), antihypertensives (p = .0075), and dyslipidemic subcategories (p = .0197). Conclusion. An intensive medical intervention may reduce pharmaceutical expenditures in severely obese individuals. These results must be viewed with caution given the high attrition of study participants.
PMID: 24977497

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