The Benefits of Reducing Sodium Consumption in the US Adult Population Academy Health Annual Research Meeting June 9, 2008 Kartika Palar, MA Roland Sturm, PhD

Palar/Sturm Academy Health 2008 Outline Background and study overview NHANES simulation model Direct health care cost savings Quality of life savings Conclusions and limitations

Palar/Sturm Academy Health 2008 Public health guidelines recommend limiting sodium intake U.S. Dietary guidelines and the IOM recommend consuming no more than 2,300 mg/d –1500 mg/d upper limit if you are black, middle aged or older, or have hypertension Healthy People 2010 target is 65% of adults consuming ≤ 2300 mg/d by 2010 American Public Health Association called for 50% reduction in sodium in nation’s food supply by 2012 Motivated by well-accepted evidence linking sodium intake with increased blood pressure

Palar/Sturm Academy Health 2008 Current intake is much higher than guidelines Percentiles of daily sodium consumption among US adults (2004) Average adult sodium intake is 3,400 mg/day* Only 30% of adults consume ≤ 2,300 mg/day* Big shift in curve won’t happen by itself *National Health and Nutrition Examination Survey (NHANES), Current consumption Percentiles of population 02,0004,0006,0008,000 Average daily sodium consumption HP 2010 target

Palar/Sturm Academy Health 2008 Food processing is the largest contributor to dietary sodium intake Added during food processing (77%) Relative contributions to dietary sodium Added during cooking (5%) Naturally occurring (12%) Added at the table (6%) Source: 2005 U.S. Dietary Guidelines; Mattes, Donnelly D. Relative contributions of dietary sodium sources. J Am Coll Nutr Aug; 10(4):

Palar/Sturm Academy Health 2008 Broad-ranging policy options to reduce sodium intake are being considered Removal of sodium’s GRAS* status by the FDA Gradual vs. steep reductions in the sodium content of processed foods Voluntary vs. enforced producer steps Social marketing campaigns to educate consumers Information on restaurant menus Improved labeling (“traffic light”?) and better heuristics for consumers *Generally Recognized As Safe.

Palar/Sturm Academy Health 2008 What are the social and economic benefits of reducing sodium intake among U.S. adults? Overall Approach: We estimate sodium intake and hypertension prevalence For different sodium reduction levels, we simulate changes in –Prevalence of adult hypertension –Health care costs –Population quality-of-life measures

Palar/Sturm Academy Health 2008 Outline Background and study overview NHANES simulation model Direct health care cost savings Quality of life savings Conclusions and limitations

Palar/Sturm Academy Health 2008 Simulation based on blood pressure and sodium intake data among U.S. adults National Health and Examination Survey, –Blood pressure (exam) –Antihypertensive medication use (interview) –Sodium intake (interview) Identified hypertensives using clinical definition: ≥ 140 mm Hg SBP, ≥ 90 mm Hg DBP, or taking antihypertensive medications

Palar/Sturm Academy Health 2008 Our analysis assumes a link between sodium and blood pressure reductions Meta-analysis on modest, long term sodium reduction calculated change in blood pressure after reducing sodium by 2,300 mg/d * We apply proportional changes for smaller reductions Blood pressure category Change in blood pressure for hypertensives (mm Hg) {95% CI} Systolic -7.2 {-8.8, -5.6} Diastolic -3.8 {-4.7, -2.8} Source: He & MacGregor (2004)

Palar/Sturm Academy Health 2008 We model the reduction in hypertension cases expected from lower population sodium intake Simulated a drop in sodium consumption to key public health target levels: 2300, 1500, & 1200 mg/d – Assumed the same underlying distribution of blood pressure for non-medicated hypertensives as medicated hypertensives – Shifted only non-medicated hypertensives to separate out sodium reduction effects Calculated the proportion of hypertensives that switched to normal blood pressure status

Palar/Sturm Academy Health 2008 Lowering population sodium intake to 2300 mg/d could reduce hypertension by 11 million cases Cases of hypertension (millions) Baseline Dietary Guidelines & IOM Upper Limit IOM Upper Limit for Middle Aged +, Hypertensives, Blacks IOM Adequate Intake for Middle Aged + 0% 20% 10% 30% 40% 1,200 1,500 2,300 3,400 Sodium intake (mg/day) Prevalence of adult hypertension

Palar/Sturm Academy Health 2008 Outline Background and study overview NHANES blood pressure simulation model Direct health care cost savings Quality of life savings Conclusions and limitations

Palar/Sturm Academy Health 2008 We calculated savings in direct health care costs due to reduced hypertension Health care costs include the cost of associated cardiovascular disease but do not include related renal disease Annual cost of hypertension = $1,598 per person (2005) * Total savings in health care costs = $1,598 x reduction in cases of hypertension Figure does not include benefits of reducing blood pressure unless hypertension status changed *Source: Trogdan et al. (2007) using MEPS data

Palar/Sturm Academy Health 2008 Reducing sodium intake to 2,300 mg/d could save $18 billion annually in health care costs Estimated annual savings in direct health care costs (billions) ,0001,5002,0002,5003,000 Average reduction in sodium consumption (mg/day) Estimated health care costs saved (2005 $) Arrows show reductions to dietary guidelines 1,500 mg 2,300 mg

Palar/Sturm Academy Health 2008 Outline Background and study overview NHANES blood pressure simulation model Direct health care cost savings Quality of life savings Conclusions and limitations

Palar/Sturm Academy Health 2008 QALYs gained were calculated for one year, ignoring extensions in life expectancy Population QALY was calculated by combining: –Number of hypertension cases averted –Increase in quality-of-life from avoided hypertension and resulting heart attack and stroke ~ $100,000 was used as the value of a QALY We calculated savings in quality-adjusted life years (QALYs) due to reduced hypertension (1)

Palar/Sturm Academy Health 2008 The change in quality-of-life (QoL) per person was calculated using parameters from the literature: Δ QoL = U HT + (U AMI * AR% AMI * P AMI ) + (U stroke * AR% stroke * P stroke ) Where: U i = utility weight increase for avoiding disease i AR% i = % of disease i attributable to hypertension P i = prevalence of disease i among hypertensives Population QALYs saved = Δ quality-of-life * cases averted *Source: Sullivan et al, 2006 (for quality of life utility weights) We calculated savings in quality-adjusted life years (QALYs) due to reduced hypertension (2)

Palar/Sturm Academy Health 2008 QALY savings may exceed those of other important public health interventions Sodium Consumption (mg/day) Population QALYs saved per year (thousands) Value (billions) * 2,300 (Dietary Guidelines) 312$32 1,500 (Dietary Guidelines for Middle Age +) 459$47 1,200 (IOM Adequate Intake for Middle Aged +) 496$50 *Using ~$100,000 per QALY (2007 $) – based on Kaplan & Bush, 1982 and updated using the CPI. Population QALYs saved (thousands) Sources: Maciosek et al. (2006), Vijan, et al. (2000)

Palar/Sturm Academy Health 2008 Outline Background and study overview NHANES blood pressure simulation model Direct health care cost savings Quality of life savings Conclusions and limitations

Palar/Sturm Academy Health 2008 Results suggest large potential savings A reduction in sodium intake to 2,300 mg/d (recommended upper intake) may save: –$18 billion in direct health care costs –$32 billion in the value of added quality of life –312,000 quality-adjusted life years annually, comparable to other population-based interventions considered Sensitivity analysis that varied the strength and non-linearity of the dose-response between sodium reduction and blood pressure did not greatly change our results Thus, the social and economic benefits of reduced sodium intake at the population level are likely to be large

Palar/Sturm Academy Health 2008 Limitations These figures only calculate benefits for reducing hypertension and not for lowering overall blood pressures Excludes other health effects associated with lower sodium Quality-adjusted life years are a lower bound –They do not take lifetime benefits into account –Some cardiovascular disease and all renal disease is excluded Medicated hypertensives may have a different underlying distribution of blood pressure than non- medicated hypertensives

Palar/Sturm Academy Health 2008 Eating Out Schlotzky Original Ham and Cheese Sandwich: 731 calories, 2,976 mg Denny’s Lumberjack Breakfast: 1,140 calories, 4,140 mg McD Premium Grilled Chicken Sandwich: 520 calories, 1,760 mg Ratio of mg sodium to calories 4:1

Palar/Sturm Academy Health 2008 Eating In – If You Use Processed Food 1 serving: 50 calories, 710 mg (sodium/calories ratio 14:1) 2 servings: 480 calories, 1,280 mg 1 cup prepared: 240 calories, 800 mg Heart Smart 1 cup: 180 calories, 860 mg Who advertises with the Healthy Heart?