We use several measures of medical care to predict disability. The first variable is the share of people who receive surgical interventions. To define relevant procedures, we identify treatments for each specific diagnosis that the medical literature has identified as being efficacious (generally in reducing mortality) for at least some subsets of patients with that diagnosis. These procedures are detailed in table 3. For hypertension, there are no generally accepted surgical therapies. There are one or more therapies for the other conditions, of which the most common appropriate procedures are “other operations on the heart and blood vessels” (CPT code 37), which includes PCI (angioplasty), heart replacement procedures and insertion of pace-makers, and “incision, excision and occlusion of vessels” (CPT code 38), which includes endarterectomies. CABG procedures for ischemic heart disease patients are coded under CPT code 36, “Operations on vessels of heart”. itat on
Table 4 shows the average rate of procedure use over time across hospital referral regions, for all cardiovascular disease patients and by specific conditions. In the 1984-89 cohort, the average procedure rate was only 21 percent across regions. The average procedure rate was highest for other circulatory diseases (30%), followed by ischemic heart disease (23%), stroke (13%) and heart failure and arrhythmia (11.3%). By 1994-1999, the average procedure rate for all patients across all regions increased to 34%. The average procedure rate for ischemic heart disease patients jumped to 48%. Average procedure rates increased to 43% for other circulatory diseases, 25% for stroke and 14.2% for heart failure and arrhythmia. These increases reflect the greater belief among physicians about the efficacy of therapy, and advances in the therapy itself.
Our other measures of medical technology involve use of pharmaceuticals for patients with acute myocardial infarction. As noted in the previous section, these pharmaceuticals have been shown to improve survival, although the overall effect of pharmaceutical treatment on both improved survival and disability in the elderly has not been well-established. Randomized studies comparing various treatments for ischemic heart disease on functional status and quality of life reported improvements for most outcome measures for both medical and surgical therapies (Rogers, Coggin et al. 1990; Strauss, Fortin et al. 1995; Hlatky, Rogers et al. 1997; Pocock, Henderson et al. 2000; Borkon, Muehlebach et al. 2002; Pfisterer, Buser et al. 2003).. However, most of these studies included patients under age 65 who may be more likely to improve than elderly patients (Rogers, Coggin et al. 1990; Strauss, Fortin et al. 1995; Hlatky, Rogers et al. 1997; Pocock, Henderson et al. 2000; Borkon, Muehlebach et al. 2002).