T. Joseph Sheehan

The geographic distribution of breast cancer incidence in Massachusetts 1988 to 1997, adjusted for covariates

BackgroundThe aims of this study were to determine whether observed geographic variations in breast cancer incidence are random or statistically significant, whether statistically significant excesses are temporary or time-persistent, and whether they can be explained by covariates such as socioeconomic status (SES) or urban/rural status?ResultsA purely spatial analysis found fourteen geographic areas that deviated significantly from randomness: ten with higher incidence rates than expected, four lower than expected. After covariate adjustment, three of the ten high areas remained statistically significant and one new high area emerged. The space-time analysis identified eleven geographic areas as statistically significant, seven high and four low. After covariate adjustment, four of the seven high areas remained statistically significant and a fifth high area also identified in the purely spatial analysis emerged.ConclusionsThese analyses identify geographic areas with invasive breast cancer incidence higher or lower than expected, the times of their excess, and whether or not their status is affected when the model is adjusted for risk factors. These surveillance findings can be a sound starting point for the epidemiologist and has the potential of monitoring time trends for cancer control activities.

Stress and low birth weight: a structural modeling approach using real life stressors.

This study presents a structural equation model describing the influence of stressful life experiences on low birth weight. Data were gathered prospectively in two waves from 5295 inner-city women as part of a city-wide preterm birth prevention project. Using interviews and the medical record, over 200 measures were gathered on each mother and her infant, where each measure was included because of its relevance documented in the risk factor literature. Seventeen of these measures reflected real life stressful experiences and through measurement modeling, eleven of these measures were chosen to represent three underlying measures of stress: economic stress, family stress, and the lack of social support. This study incorporates these psychosocial stressors into a full structural equation model to show their influence on addictive behavior and low birth weight. The full model emerged from tests of alternative causal conceptualizations of how these stressors influence each other and low birth weight--whether their influence on low birth weight in simple and direct, or whether their influence is mediated by addictive behaviors. The model was tested on the first wave, a sample of 3205, and cross-validated on the second wave, a sample of 2090. The model shows that economic stress influences both social support and family stress, but has no direct influence on low birth weight: that social support, or its absence, influences addictive behavior, but has no direct influence on low birth weight, and that family stress influences addictive behavior, and consistent with 30 years of research on humans, has no direct influence on low birth weight. Finally, the mothers history of medical risks shows an independent influence on low birth weight, while her age does not. Age, however, shows a strong influence on addictive behavior. The study demonstrates how structural equation modeling can be used to create and test alternative conceptualizations of how stress affects low birth weight. There are strong implications for planners of prenatal care programs.

Risk Factors for Hospitalization Among Medicare Home Care Patients

This study determined factors associated with an increased risk of ending Medicare home health care because of hospitalization and examined specific types of and reasons for hospitalization. Sample members (N = 922) were followed from admission to discharge as they received home care from Ohio Medicare-certified home care agencies between December 1999 and March 2002. Potential patient-level risk factors were predisposing, enabling, or need variables, and an agency-level variable denoting hospital affiliation or free-standing status was examined as a second-level risk factor. Among those hospitalized (18.3%), more than 80.0% experienced emergency hospitalizations, mostly for acute exacerbations of chronic diseases. Statistically significant risk factors for hospitalization included dyspnea severity, functional disability level, skin or wound problems, diabetes, case mix score, and guarded rehabilitation prognosis. Home care agencies might reduce hospitalizations by using clinical prognosis as a key resource for team communication and by helping patients and families anticipate potential acute exacerbations of chronic diseases and manage these events at home.

Measuring disability in Medicare home care patients: application of Rasch modeling to the outcome and assessment information set.

Background. The Outcome and Assessment Information Set (OASIS) is the universal clinical assessment tool for adult nonmaternity patients receiving skilled care at home from Medicare-certified home health agencies in the United States. Anticipating increased use of OASIS data for research purposes, this article explored the usefulness of Rasch modeling to address disability measurement challenges presented by the unique response category structure of the seven activities of daily living (ADL) and eight instrumental ADL (IADL) items in the OASIS. Objectives. To illustrate how Rasch model statistics can be used to evaluate OASIS ADL and IADL item unidimensionality and model fit; to illustrate how Rasch modeling simultaneously estimates ADL and IADL item difficulty, thresholds between item response categories, and person disability; and to compare Rasch estimates of item difficulty and person disability scores to estimates based on more conventional Likert scoring techniques. Subjects. Medicare-eligible home health care patients (n = 583) served by one of 12 home care agencies in Ohio between November 1999 and September 2000. Measures. ADL and IADL items were measured three ways: according to the original OASIS scoring (raw Likert); transformed raw Likert scores accounting for the nonuniform item structure (corrected Likert); and Rasch Partial Credit model scores. Results. The items bathing and telephone use showed evidence of unexpected response patterns; recoding of these items was necessary for good Rasch model fit. Partial Credit model results revealed that interval distances between response categories varied widely across the 15 ADL and IADL items. When ADL and IADL items were ranked by level of difficulty, results were similar between Rasch and corrected Likert measurement approaches; however, corrected Likert person scores were found to be nonlinear at highest and lowest disability levels when plotted against Rasch person scores. Conclusions. Rasch modeling can help improve the precision of disability measurement in Medicare home care patients when using ADL and IADL items from the OASIS instrument.

A space-time analysis of the proportion of late stage breast cancer in Massachusetts, 1988 to 1997

BackgroundEarly detection is the best way to control breast cancer. This observational epidemiologic study uses ten years of data, 1988–1997, to determine whether the observed variations in the proportion of breast cancers diagnosed at late stage are simply random or are statistically significant with respect to both geographical location and time.ResultsA total of three spatial-temporal areas were found to deviate significantly from randomness in the unadjusted analysis; one of the three areas contained statistically significant excesses in proportion of late stage, while two areas were identified as significantly lower than expected. The area of excess spanned the first three years of the study period, while the low areas spanned the last five years of the study period. Some of these areas were no longer statistically significant when adjustments were made for SES and urban/rural status.ConclusionAlthough there was an area of excess in eastern Massachusetts, it only spanned the first three years of the study period. The low areas were fairly consistent, spanning the last five years of the study period.

Structural Equation Models of Moral Reasoning and Physician Performance

In order to identify and explain those aspects of clinical performance related to moral reasoning, 39 family medicine residents were studied as they interacted with each of two simulated patients. Residents were interviewed to assess their performance with each patient, elicit their general philosophy of being a doctor, and measure their moral reasoning. General performance as residents was rated by three faculty supervisors. Scoringprotocols were developedfor each measure to ensure objectivity. Factor analysis of each measure guided selection of the most meaningful variablefrom each instrument. Based upon general models relating attitude to behavior, structural equations were used to explicate the relationship between moral reasoning, performance on the simulated cases, performance as a resident, attitude, and intention. Chi-square goodness offit indicates that the general attitude-behavior models adequatelyfit the data. These models would suggest that moral reasoning and physician attitudes have more of an influence on behavior than physician intentions.

Spatial analysis of colorectal cancer incidence and proportion of late-stage in Massachusetts residents: 1995–1998

BackgroundThe aims of this study were to determine if observed geographic variations in colorectal cancer incidence are simply random or are statistically significant deviations from randomness, whether statistically significant excesses are temporary or persistent, and whether they can be explained by risk factors such as socioeconomic status (SES) or the percent of the population residing in an urban area rather than a rural area. Between 1995 and 1998, 6360 male and 6628 female invasive colorectal cancer cases were diagnosed in Massachusetts residents. Cases were aggregated to Census tracts and analyzed for deviations from random occurrence with respect to both location and time.ResultsSix geographic areas that deviated significantly from randomness were uncovered in the age-adjusted analyses of males: three with higher incidence rates than expected and eight lower than expected. In the age-adjusted analyses of females, one area with a higher incidence rate, and one area with a lower incidence rate than expected, were found. After adjustment for SES and percent urban, some of these areas were no longer significantly different.ConclusionPublic health practitioners can use the results of this study to focus their attention onto areas in Massachusetts that need to increase colorectal screening or have elevated risk of colorectal cancer incidence.

History of affective disorder and the temporal trajectory of fatigue in rheumatoid arthritis

This study examines whether the general level and rate of change of fatigue over time is different for those rheumatoid arthritis (RA) patients with and those without a history of affective disorder (AD). Four hundred fifteen RA patients from a national panel had yearly telephone interviews to obtain fatigue and distress reports, and a one-time semistructured assessment of the history of depression and generalized anxiety disorder. Growth-curve analysis was used to capture variations in initial fatigue levels and changes in fatigue over 7 years for those with and without a history. RA patients with a history of major AD reported levels of fatigue that were 10% higher than those without a history in the 1st year of the study. Their fatigue reports remained elevated over 7 years. Further analysis showed that the effects of a history of AD on fatigue are fully mediated through current distress, although those with a history had a significantly smaller distress-fatigue slope. Thus, a history of AD leaves RA patients at risk for a 7-year trajectory of fatigue that is consistently higher than that of patients without a history. The elevation in fatigue reports is, at least in part, a function of enduring levels of distress.

Risk Factors for Hospitalization in a National Sample of Medicare Home Health Care Patients

Acute care hospitalization during or immediately following a Medicare home health care (HHC) episode is a major adverse outcome, but little has been published about HHC patient-level risk factors for hospitalization. The authors determined risk factors at HHC admission associated with subsequent acute care hospitalization in a nationally representative Medicare patient sample (N = 374,123). Hospitalization was measured using Medicare claims data; risk factors were measured using Outcome Assessment and Information Set data. Seventeen percent of sample members were hospitalized. Multivariate logistic regression analysis found that the most influential risk factors (all p < .001) were skin wound as primary HHC diagnosis, clinician-judged guarded rehabilitation prognosis, congestive heart failure as primary HHC diagnosis, presence of depressive symptoms, dyspnea severity, and Black, compared to White. HHC initiatives that minimize chronic condition exacerbations and actively treat depressive symptoms might help reduce Medicare patient hospitalizations. Unmeasured reasons for higher hospitalization rates among Black HHC patients deserve further investigation.

The geographic distribution of melanoma incidence in Massachusetts, adjusted for covariates

BackgroundThe aims of this study were to determine whether observed geographic variations in melanoma cancer incidence in both gender groups are simply random or are statistically significant, whether statistically significant excesses are temporary or persistent, and whether they can be explained by risk factors such as socioeconomic status (SES) or the percent of the population residing in an urban rather than a rural area. Between 1990 and 1999, 4774 female and 5688 male melanomas were diagnosed in Massachusetts residents. Cases were aggregated to census tracts and analyzed for deviations from random occurrence with respect to both spatial location and time.ResultsThirteen geographic areas that deviated significantly from randomness were uncovered in the age-adjusted analyses of males: five with higher incidence rates than expected and eight lower than expected. In the age-adjusted analyses of females, six areas with higher incidence rates and eight areas with lower than expected incidence rates were found. After adjustment for SES and percent urban, several of these areas were no longer significantly different.ConclusionThese analyses identify geographic areas with invasive melanoma incidence higher or lower than expected, the times of their excess, and whether or not their status is affected when the model is adjusted for risk factors. These surveillance findings can be a sound starting point for the shoe-leather epidemiologist.