Contributions of Health Care to Longevity: A Review of 4 Estimation Methods

Robert M. Kaplan; Arnold Milstein

doi:10.1370/afm.2362

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Table 1

Summary of the Data Sources and Analysis Methods

Study	Population	Data Source	Analysis Method
McGinnis,⁸ Schroeder⁶	US population	US Vital Statistics	Examined PAF for a range of risk factors associated with defined causes of death. Summed PAF for each determinant across various causes of death
Wennberg¹¹	US Medicare recipients aged ≥65 years enrolled in Parts A and B in 2007	Medicare claims. Deaths among Medicare recipients in 2007	Evaluated variation in use of health care and age, sex, and race adjusted mortality across 306 HRRs. Applied regression with adjustments for medical diagnoses, poverty, and a behavioral index
Park¹²	US population aggregated at the county level	2010-2013 County Health Rankings and Roadmaps database included 2,996 (95%) of US counties	LGCM used to estimate health outcome, which was a combination of morbidity and mortality. Four factors (behaviors, clinical care, social/economic, and physical environment) used to explain health outcomes with statistical adjustment for yearly variation and state specific characteristics
Newhouse¹⁰	2,750 families including 7,700 individuals aged <65 years randomly assigned to different levels of cost sharing^a and followed 3-5 years	Health surveys and physical examinations administered at the beginning and end of the study	Comparisons of experimental groups for self-reported outcomes. Similar comparisons for clinical diagnoses, including hypertension, vision, dental health, and serious symptoms

HRR = hospital referral region; LGCM = latent growth curve modeling; PAF = population attributable fraction; US = United States.
↵a Levels of cost sharing were 0% (free medical care), 25%, 50%, or 95%.

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Table 2
Summary of Estimates from 4 Methods
Study Social Circumstances Behavior Patterns Medical Care
McGinnis,⁸ Schroeder⁶ 15 40 7-10
Wennberg¹¹ 29^a 65^b 5-17^c
Park¹² 25-46^d 16-29^d 7-17^d
Newhouse¹⁰ NE NE 0-10
LGCM = latent growth curve modeling; NE = not estimated.
↵a Includes 19% based on poverty index + 10% from age, race, sex adjustment.
↵b Based on a population health index that includes obesity, smoking status, and self-reported poor physical health days/month.
↵c Low estimated from Hierarchical Condition Cluster (HCC); high estimated from HCC adjusted for demographic variables.
↵d Low estimates based on Krieger’s suggestion that reported numbers should be adjusted by the percentage of variance in outcomes accounted for LCGM by the model.13 This was accomplished by multiplying each estimate by 54%.

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The Article in Brief

Contributions of Health Care to Longevity: A Review of 4 Estimation Methods

Robert M. Kaplan , and colleagues

Background A widely cited statistic suggests that health care services account for only a small percentage of the variation in American life expectancy. However, the methodology supporting the finding has been challenged. To explore the robustness of the finding, a new report examines four methods that rely on different outcome measures, analytic techniques, and data sets to consider the percentage of premature deaths or poor health outcomes that can be attributed to health care and other factors.

What This Study Found Health care services account for only a small percentage of the variation in American life expectancy, according to the report. Estimates from four methods suggest that health care accounts for between 5% and 15% of the variation in premature death. In contrast, behavioral and social factors account for a much higher percentage of variation in premature mortality, ranging from 16% to 65%. This analysis affirms previous findings that health care is only one component of a larger set of influences on health outcomes.

Implications

The authors suggest that a more diversified portfolio of national investments would generate a higher health yield. For example, spending on non-medical social services for each dollar spent on medical care averages about two dollars in wealthy countries that report data to the Organization for Economic Cooperation and Development compared to 55 cents in the United States.
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