Benefits of commercial weight-loss programs on blood pressure and lipids: a systematic review

Abstract

Our objective was to compare the effect of commercial weight-loss programs on blood pressure and lipids to control/education or counseling among individuals with overweight/obesity. We conducted a systematic review by searching MEDLINE and Cochrane Database of Systematic Reviews from inception to November 2014 and references identified by the programs. We included randomized, controlled trials ≥12weeks in duration. Two reviewers extracted information on study design, interventions, and mean change in systolic blood pressure (SBP), diastolic blood pressure (DBP), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), triglycerides, and total cholesterol and assessed risk of bias. We included 27 trials. Participants' blood pressure and lipids were normal at baseline in most trials. At 12months, Weight Watchers showed little change in blood pressure or lipid outcomes as compared to control/education (2 trials). At 12months, Atkins' participants had higher HDL-c and lower triglycerides than counseling (4 trials). Other programs had inconsistent effects or lacked long-term studies. Risk of bias was high for most trials of all programs. In conclusion, limited data exist regarding most commercial weight-loss programs' long-term effects on blood pressure and lipids. Clinicians should be aware that Weight Watchers has limited data that demonstrate CVD risk factor benefits relative to control/education. Atkins may be a reasonable option for patients with dyslipidemia. Additional well-designed, long-term trials are needed to confirm these conclusions and evaluate other commercial programs.

Keywords: Blood pressure; Cholesterol; Commercial weight-loss programs; Risk factors.

Figure 1. Summary of evidence search and selection

*Trials with ineligible study designs (e.g., retrospective case series or RCTs <12 weeks in duration) or ineligible programs (e.g., not available in the United States). **Used medications or supplements; modified specifically for the study; unavailable in the United States; or available only to special populations (e.g., active-duty military personnel or veterans). Abbreviations: CDSR — Cochrane Database of Systematic Reviews; RCT — randomized, controlled trial.

Figure 2. Difference in mean systolic blood pressure (SBP) change in mmHg between commercial programs and comparators at 6 and 12 months, displayed by program type

Panel A displays 6-month results and Panel B displays 12-month results. Diamond size is standardized across trials and does not reflect the sample size analyzed. Risk of bias (ROB) reflects overall assessment of each outcome at the time point for that trial, which were determined based on ratings of selection, detection, attrition, and reporting biases. “Attrition” reflects the percentage of participants unavailable for outcome measurement at that time point or weight measurement if N analyzed was not reported. *Results reported in >1 article. †Analysis did not use intention-to-treat approach (e.g., completers’ only). ‡Between-group differences inferred from results provided (e.g., analysis of change over time in each study arm). §Overall attrition at time point. Abbreviations: C — comparator group; DM — overweight or obese patients with diabetes mellitus; GEN — general population of overweight and obese patients; LC — low-carbohydrate version of program; NR — not reported; P — commercial program group; ROB – risk of bias; SBP – systolic blood pressure; WW — Weight Watchers.

Figure 3. Difference in mean diastolic blood pressure (DBP) change in mmHg between commercial programs and comparators at 6 and 12 months, displayed by program type

Panel A displays 6-month results and Panel B displays 12-month results. Diamond size is standardized across trials and does not reflect the sample size analyzed. Risk of bias (ROB) reflects overall assessment of each outcome at the time point for that trial, which were determined based on ratings of selection, detection, attrition, and reporting biases. “Attrition” reflects the percentage of participants unavailable for outcome measurement at that time point or weight measurement if N analyzed was not reported. *Results reported in >1 article. †Analysis did not use intention-to-treat approach (e.g., completers’ only). ‡Between-group differences inferred from results provided (e.g., analysis of change over time in each study arm). §Overall attrition at time point. Abbreviations: C — comparator group; DBP – diastolic blood pressure; DM — overweight or obese patients with diabetes mellitus; GEN — general population of overweight and obese patients; LC — low-carbohydrate version of program; NR — not reported; P — commercial program group; ROB – risk of bias; WW — Weight Watchers.

Figure 4. Difference in mean low-density lipoprotein cholesterol (LDL-c) change in mg/dL between commercial programs and comparators at 6 and 12 months, displayed by program type

Panel A displays 6-month results and Panel B displays 12-month results. Diamond size is standardized across trials and does not reflect the sample size analyzed. Risk of bias (ROB) reflects overall assessment of each outcome at the time point for that trial, which were determined based on ratings of selection, detection, attrition, and reporting biases. “Attrition” reflects the percentage of participants unavailable for outcome measurement at that time point or weight measurement if N analyzed was not reported. To convert units from mg/dL to mmol/L, multiply by 0.02586. *Results reported in >1 article. †Analysis did not use intention-to-treat approach (e.g., completers’ only). ‡Between-group differences inferred from results provided (e.g., analysis of change over time in each study arm). §Overall attrition at time point. Abbreviations: C — comparator group; DM — overweight or obese patients with diabetes mellitus; GEN — general population of overweight and obese patients; HMR – Health Management Resources; LC — low-carbohydrate version of program; LDL-c – low-density lipoprotein cholesterol; NR — not reported; P — commercial program group; ROB – risk of bias; T – telephone-based program; WW — Weight Watchers.

Figure 5. Difference in mean high-density lipoprotein cholesterol (HDL-c) change in mg/dL between commercial programs and comparators at 6 and 12 months, displayed by program type

Panel A displays 6-month results and Panel B displays 12-month results. Diamond size is standardized across trials and does not reflect the sample size analyzed. Risk of bias (ROB) reflects overall assessment of each outcome at the time point for that trial, which were determined based on ratings of selection, detection, attrition, and reporting biases. “Attrition” reflects the percentage of participants unavailable for outcome measurement at that time point or weight measurement if N analyzed was not reported. To convert units from mg/dL to mmol/L, multiply by 0.02586. *Results reported in >1 article. †Analysis did not use intention-to-treat approach (e.g., completers’ only). ‡Between-group differences inferred from results provided (e.g., analysis of change over time in each study arm). §Overall attrition at time point. Abbreviations: C — comparator group; DM — overweight or obese patients with diabetes mellitus; GEN — general population of overweight and obese patients; HDL-c – high-density lipoprotein cholesterol; LC — low-carbohydrate version of program; NR — not reported; P — commercial program group; ROB – risk of bias; T – telephone-based program; WW — Weight Watchers.

Figure 6. Difference in mean triglyceride (TG) change in mg/dL between commercial programs and comparators at 6 and 12 months, displayed by program type

Panel A displays 6-month results and Panel B displays 12-month results. Diamond size is standardized across trials and does not reflect the sample size analyzed. Risk of bias (ROB) reflects overall assessment of each outcome at the time point for that trial, which were determined based on ratings of selection, detection, attrition, and reporting biases. “Attrition” reflects the percentage of participants unavailable for outcome measurement at that time point or weight measurement if N analyzed was not reported. To convert units from mg/dL to mmol/L, multiply by 0.01129. *Results reported in >1 article. †Analysis did not use intention-to-treat approach (e.g., completers’ only). ‡Between-group differences inferred from results provided (e.g., analysis of change over time in each study arm). §Overall attrition at time point. Abbreviations: C — comparator group; DM — overweight or obese patients with diabetes mellitus; GEN — general population of overweight and obese patients; LC — low-carbohydrate version of program; NR — not reported; P — commercial program group; ROB – risk of bias; T – telephone-based program; TG – triglyceride; WW — Weight Watchers.

Figure 7. Difference in mean total cholesterol (TC) change in mg/dL between commercial programs and comparators at 6 and 12 months, displayed by program type

Panel A displays 6-month results and Panel B displays 12-month results. Diamond size is standardized across trials and does not reflect the sample size analyzed. Risk of bias (ROB) reflects overall assessment of each outcome at the time point for that trial, which were determined based on ratings of selection, detection, attrition, and reporting biases. “Attrition” reflects the percentage of participants unavailable for outcome measurement at that time point or weight measurement if N analyzed was not reported. To convert units from mg/dL to mmol/L, multiply by 0.02586. *Results reported in >1 article. †Analysis did not use intention-to-treat approach (e.g., completers’ only). ‡Between-group differences inferred from results provided (e.g., analysis of change over time in each study arm). §Overall attrition at time point. Abbreviations: C — comparator group; DM — overweight or obese patients with diabetes mellitus; GEN — general population of overweight and obese patients; LC — low-carbohydrate version of program; NR — not reported; P — commercial program group; ROB – risk of bias; T – telephone-based program; TC – total cholesterol; WW — Weight Watchers.