Donald S. Shepard

A two-dimensional interpolation function for irregularly-spaced data

In many fields using empirical areal data there arises a need for interpolating from irregularly-spaced data to produce a continuous surface. These irregularly-spaced locations, hence referred to as “data points,” may have diverse meanings: in meterology, weather observation stations; in geography, surveyed locations; in city and regional planning, centers of data-collection zones; in biology, observation locations. It is assumed that a unique number (such as rainfall in meteorology, or altitude in geography) is associated with each data point. In order to display these data in some type of contour map or perspective view, to compare them with data for the same region based on other data points, or to analyze them for extremes, gradients, or other purposes, it is extremely useful, if not essential, to define a continuous function fitting the given values exactly. Interpolated values over a fine grid may then be evaluated. In using such a function it is assumed that the original data are without error, or that compensation for error will be made after interpolation.

The healthcare costs of sarcopenia in the United States

Objectives: To estimate the healthcare costs of sarcopenia in the United States and to examine the effect that a reduced sarcopenia prevalence would have on healthcare expenditures.

Use of Cardiac Rehabilitation by Medicare Beneficiaries After Myocardial Infarction or Coronary Bypass Surgery

Background— Cardiac rehabilitation (CR) is effective in prolonging survival and reducing disability in patients with coronary heart disease. However, national use patterns and predictors of CR use have not been evaluated thoroughly. Methods and Results— Using Medicare claims, we analyzed outpatient (phase II) CR use after hospitalizations for acute myocardial infarctions or coronary artery bypass graft surgery in 267 427 fee-for-service beneficiaries aged ≥65 years who survived for at least 30 days after hospital discharge. We used multivariable analyses to identify predictors of CR use and to quantify geographic variations in its use. We obtained unadjusted, adjusted-smoothed, and standardized rates of CR use by state. Overall, CR was used in 13.9% of patients hospitalized for acute myocardial infarction and 31.0% of patients who underwent coronary artery bypass graft surgery. Older individuals, women, nonwhites, and patients with comorbidities (including congestive heart failure, previous stroke, diabetes mellitus, or cancer) were significantly less likely to receive CR. Coronary artery bypass graft surgery during the index hospitalization, higher median household income, higher level of education, and shorter distance to the nearest CR facility were important predictors of higher CR use. Adjusted CR use varied 9-fold among states, ranging from 6.6% in Idaho to 53.5% in Nebraska. The highest CR use rates were clustered in the north central states of the United States. Conclusions— CR use is relatively low among Medicare beneficiaries despite convincing evidence of its benefits and recommendations for its use by professional organizations. Use is higher after coronary artery bypass graft surgery than with acute myocardial infarctions not treated with revascularization procedures and varies dramatically by state and region of the United States.

The Global Burden of Disease Study 2010: Interpretation and Implications for the Neglected Tropical Diseases

The publication of the Global Burden of Disease Study 2010 (GBD 2010) and the accompanying collection of Lancet articles in December 2012 provided the most comprehensive attempt to quantify the burden of almost 300 diseases, injuries, and risk factors, including neglected tropical diseases (NTDs) [1]–[3]. The disability-adjusted life year (DALY), the metric used in the GBD 2010, is a tool which may be used to assess and compare the relative impact of a number of diseases locally and globally [4]–[6]. Table 1 lists the major NTDs as defined by the World Health Organization (WHO) [7] and their estimated DALYs [1]. With a few exceptions, most of the NTDs currently listed by the WHO [7] or those on the expanded list from PLOS Neglected Tropical Diseases [8] are disablers rather than killers, so the DALY estimates represent one of the few metrics available that could fully embrace the chronic effects of these infections. Table 1 Estimated DALYs (in millions) of the NTDs from the Global Burden of Disease Study 2010. Disease DALYs from GBD 2010 (numbers in parentheses indicate 95% confidence intervals) [1] NTDs 26.06 (20.30–35.12) Intestinal nematode infections 5.19 (2.98–8.81) Hookworm disease 3.23 (1.70–5.73) Ascariasis 1.32 (0.71–2.35) Trichuriasis 0.64 (0.35–1.06) Leishmaniasis 3.32 (2.18–4.90) Schistosomiasis 3.31 (1.70–6.26) Lymphatic filariasis 2.78 (1.8–4.00) Food-borne trematodiases 1.88 (0.70–4.84) Rabies 1.46 ((0.85–2.66) Dengue 0.83 (0.34–1.41) African trypanosomiasis 0.56 (0.08–1.77) Chagas disease 0.55 (0.27–1.05) Cysticercosis 0.50 (0.38–0.66) Onchocerciasis 0.49 (0.36–0.66) Trachoma 0.33 (0.24–0.44) Echinococcosis 0.14 (0.07–0.29) Yellow fever <0.001 Other NTDs * 4.72 (3.53–6.35) Open in a separate window * Relapsing fevers, typhus fever, spotted fever, Q fever, other rickettsioses, other mosquito-borne viral fevers, unspecified arthropod-borne viral fever, arenaviral haemorrhagic fever, toxoplasmosis, unspecified protozoal disease, taeniasis, diphyllobothriasis and sparganosis, other cestode infections, dracunculiasis, trichinellosis, strongyloidiasis, enterobiasis, and other helminthiases. Even DALYs, however, do not tell the complete story of the harmful effects from NTDs. Some of the specific and potential shortcomings of GBD 2010 have been highlighted elsewhere [9]. Furthermore, DALYs measure only direct health loss and, for example, do not consider the economic impact of the NTDs that results from detrimental effects on school attendance and child development, agriculture (especially from zoonotic NTDs), and overall economic productivity [10], [11]. Nor do DALYs account for direct costs of treatment, surveillance, and prevention measures. Yet, economic impact has emerged as an essential feature of the NTDs, which may trap people in a cycle of poverty and disease [10]–[12]. Additional aspects not considered by the DALY metrics are the important elements of social stigma for many of the NTDs and the spillover effects to family and community members [13], [14], loss of tourism [15], and health system overload (e.g., during dengue outbreaks). Ultimately NTD control and elimination efforts could produce social and economic benefits not necessarily reflected in the DALY metrics, especially among the most affected poor communities [11].

Efficacy of pneumococcal vaccine in high-risk patients. Results of a Veterans Administration Cooperative Study.

We conducted a randomized, double-blind, placebo-controlled trial to test the efficacy of the 14-valent pneumococcal capsular polysaccharide vaccine in 2295 high-risk patients (patients with one or more of the following: age above 55 years and the presence of chronic cardiac, pulmonary, renal, or hepatic disease, alcoholism, or diabetes mellitus). Seventy-one episodes of proved or probable pneumococcal pneumonia or bronchitis occurred among 63 of the patients (27 placebo recipients and 36 vaccine recipients). Vaccine-serotype Streptococcus pneumoniae strains were recovered in association with 11 infections in the placebo group and 14 infections in the vaccine group. Pneumococcal infections occurred most frequently among patients with chronic pulmonary, cardiac, or renal diseases. Among vaccine recipients who subsequently had vaccine-type pneumonia or bronchitis, the majority did not make or sustain serum antibodies against their infecting organism in concentrations that were twice as high as the base-line values, or more than 400 ng of antibody nitrogen per milliliter, although their base-line levels were higher than those in subjects in whom infection did not develop. We were unable to demonstrate any efficacy of the pneumococcal vaccine in preventing pneumonia or bronchitis in this population. Our data suggest that chronically ill patients, who are most susceptible to infection, may have an impaired immune response to the pneumococcal vaccine.

Treatment and care for injecting drug users with HIV infection: a review of barriers and ways forward

We review evidence for effectiveness, cost-effectiveness, and coverage of antiretroviral therapy (ART) for injecting drug users (IDUs) infected with HIV, with particular attention to low-income and middle-income countries. In these countries, nearly half (47%) of all IDUs infected with HIV are in five nations--China, Vietnam, Russia, Ukraine, and Malaysia. In all five countries, IDU access to ART is disproportionately low, and systemic and structural obstacles restrict treatment access. IDUs are 67% of cumulative HIV cases in these countries, but only 25% of those receiving ART. Integration of ART with opioid substitution and tuberculosis treatment, increased peer engagement in treatment delivery, and reform of harmful policies--including police use of drug-user registries, detention of drug users in centres offering no evidence-based treatment, and imprisonment for possession of drugs for personal use--are needed to improve ART coverage of IDUs.

Cardiac Rehabilitation and Survival in Older Coronary Patients

OBJECTIVES This study assessed the effects of cardiac rehabilitation (CR) on survival in a large cohort of older coronary patients. BACKGROUND Randomized controlled trials and meta-analyses have shown that CR improves survival. However, trial participants have been predominantly middle-aged, low- or moderate-risk, white men. METHODS The population consisted of 601,099 U.S. Medicare beneficiaries who were hospitalized for coronary conditions or cardiac revascularization procedures. One- to 5-year mortality rates were examined in CR users and nonusers using Medicare claims and 3 analytic techniques: propensity-based matching, regression modeling, and instrumental variables. The first method used 70,040 matched pairs, and the other 2 techniques used the entire cohort. RESULTS Only 12.2% of the cohort used CR, and those users averaged 24 sessions. Each technique showed significantly lower (p < 0.001) 1- to 5-year mortality rates in CR users than nonusers. Five-year mortality relative reductions were 34% in propensity-based matching, 26% from regression modeling, and 21% with instrumental variables. Mortality reductions extended to all demographic and clinical subgroups including patients with acute myocardial infarctions, those receiving revascularization procedures, and those with congestive heart failure. The CR users with 25 or more sessions were 19% relatively less likely to die over 5 years than matched CR users with 24 or fewer sessions (p < 0.001). CONCLUSIONS Mortality rates were 21% to 34% lower in CR users than nonusers in this socioeconomically and clinically diverse, older population after extensive analyses to control for potential confounding. These results are of similar magnitude to those observed in published randomized controlled trials and meta-analyses in younger, more selected populations.

Economic Impact of Dengue Illness in the Americas

The growing burden of dengue in endemic countries and outbreaks in previously unaffected countries stress the need to assess the economic impact of this disease. This paper synthesizes existing studies to calculate the economic burden of dengue illness in the Americas from a societal perspective. Major data sources include national case reporting data from 2000 to 2007, prospective cost of illness studies, and analyses quantifying underreporting in national routine surveillance systems. Dengue illness in the Americas was estimated to cost

Overcoming Language Barriers in Health Care: Costs and Benefits of Interpreter Services

2.1 billion per year on average (in 2010 US dollars), with a range of

Where Now for Saving Lives

1–4 billion in sensitivity analyses and substantial year to year variation. The results highlight the substantial economic burden from dengue in the Americas. The burden for dengue exceeds that from other viral illnesses, such as human papillomavirus (HPV) or rotavirus. Because this study does not include some components (e.g., vector control), it may still underestimate total economic consequences of dengue.