Americans have gained an extraordinary 33 years in average life span over the past century. A baby born today can expect to live an average of 78 years, compared with 45 years back in 1900. But those gains have not been uniform across the nation. Columbia University economist Frank Lichtenberg reports in a new study that, while average life expectancy increased by 2.33 years nationwide from 1991 to 2004, the increase varied widely among states. Residents of New York gained 4.3 years, the most of any state, during the 13-year period studied and can expect to live 79.2 years. Oklahomans, however, gained only 0.3 years over the same period, to 75.4. (For a table listing all the states, click here.)
Lichtenberg measured a number of variants that might explain this gap, including obesity, smoking, income, health insurance coverage, and the incidence of AIDS. He discovered that a primary reason for greater gains in life span is access to new drugs and other medical innovations. For each state, he determined the year that commonly prescribed drugs won Food & Drug Administration approval, and found that those states that skewed toward newer drugs tended to have above-average increases in longevity, when adjusted for other factors.
Multiple Factors at Work
In New York, for example, the average drug approval year for patients covered by Medicaid was 1977, compared with 1976 for Oklahoma. Plus, says Lichtenberg, those states also had higher productivity, increasing output per employee by about 1% per year. He attributes the productivity gains to reduced absenteeism from illness.
State-by-state variation in prescription drug use is determined by prescribing patterns, variation in disease prevalence, and the drugs that a particular state's Medicare and Medicaid programs are willing to cover. Lichtenberg writes that there are two ways to improve health-care quality: by ensuring that patients get "best practice" care and by "shifting the technological frontier" through the use of new drugs, devices, and procedures. "Certain trends are increasing longevity and others are reducing it," he says. "I'm trying to figure out how much each of these trends contributes."
Over the period Lichtenberg studied a huge number of innovative drugs have been introduced, from Pfizer's (PFE) Lipitor and Merck's (MRK) Zocor for high cholesterol to Genentech's (DNA) Herceptin and Novartis' (NVS) Gleevec for cancer, all of which seeped into the health-care system at different rates depending on doctors' prescription habits, state Medicare and Medicaid standards, and insurance coverage.
Advocating Free-Market Solutions
Lichtenberg's study was published by the Manhattan Institute, a nonprofit conservative think tank that advocates free-market solutions to the nation's problems. He has done other studies looking at the economic impact of drug spending, which is increasing at a faster rate than any other sector of the health-care system. "In general it's been hard to answer what the payoff for increased spending on drugs," he says. "I'm trying to figure that out."
In his newest study, Lichtenberg admits to at least one confounding finding: As the nation has gotten wealthier, an inverse relationship has developed between income growth and life expectancy gains. "This could be because of increased stress or air pollution," he speculates. Other studies have found the same relationship, and no one has yet figured out why, he says.
The least surprising finding, however, is that obesity lowered life span increases significantly, wiping out much of the gain from medical innovations. Lichtenberg estimates that if obesity and income had not increased since 1991, average life expectancy nationwide would have increased by 3.88 years rather than 2.33. However, declines in smoking and the incidence of AIDS did slightly offset the rise in obesity, he notes. The full study can be found at the Manhattan Institute's Center for Medical Progress Web site.