Jesse S. Metzger

Utilizing harmonization and common surveillance methods to consolidate 4 cohorts: the Western Alaska Tribal Collaborative for Health (WATCH) study

Background According to health status reports, chronic disease prevalence appears to be rising in western Alaska Native (AN) people, and accurate population-based data are needed. Four cohort studies of western AN people were conducted in the Norton Sound and Yukon-Kuskokwim regions, but none have been large enough to allow reliable estimates of rates of chronic diseases and evaluate their risk factors. Objective In this article, the methods used to combine 4 major cohort studies of rural western AN people are described and the benefits and challenges encountered in combining data and standardizing surveillance methods for these studies are discussed. Design Tribal permission was obtained for each cohort study and the consolidated study. Data from baseline exams were directly combined or harmonized into new variables. Common surveillance methods were developed and implemented to identify incidence and risk factors for cardiovascular disease (CVD) events and type 2 diabetes. Results A cohort of 4,569 western AN participants (2,116 men and 2,453 women), aged 18–95 years, was established to study CVD and diabetes prevalence. Prospective surveillance data over an average 6.7-year follow-up can now be used to study CVD and diabetes incidence and associated risk factors in a subset of 2,754 western AN participants (1,218 men and 1,536 women) who consented to initial surveillance. Conclusions The combined cohort provides statistical power to examine incidence rates and risk factors for CVD and diabetes and allows for analyses by geographic region. The data can be used to develop intervention programmes in these populations and others.

Cardiometabolic correlates of low type 2 diabetes incidence in western Alaska Native people - The WATCH study.

AIMS Previously rare among Alaska Native (AN) people, type 2 diabetes (DM2) prevalence as indicated by registry data has increased by as much as 300% in some western Alaska regions. We sought to determine prevalence and incidence of DM2 and analyze associated cardiometabolic risk factors in western AN people. METHODS DM2 and prediabetes prevalence and incidence were determined by the Western Alaska Tribal Collaborative for Health using consolidated data from cohort studies conducted during 2000-2010. Crude and age-adjusted incidence for DM2 and prediabetes were calculated using 2010 American Diabetes Association criteria. Effects of covariates on DM2 and prediabetes were determined using univariate and multivariate Cox proportional hazards analyses, adjusted for age and sex. RESULTS Excluding baseline diabetes (n=124, 4.5%), 53 cases of new DM2 were identified among 2630 participants. Age- and sex-adjusted DM2 incidence was 4.3/1000 (95% CI 2.9, 5.0) person-years over an average 5.9-year follow up. After excluding baseline prediabetes, 387 new cases of prediabetes were identified among 1841 participants; adjusted prediabetes incidence was 44.5/1000 (95% CI 39.5, 49.5) person years. Independent predictors for DM2 included age, impaired fasting glucose, and metabolic syndrome; family history of diabetes and obesity were additional independent predictors for prediabetes. CONCLUSIONS DM2 incidence in western AN people is substantially lower than that for U.S. whites; however, incidence of prediabetes is more than 10-fold higher than western AN DM2 incidence and more closely aligned with U.S. rates. Interventions aimed at achieving healthy lifestyles are needed to minimize risk factors and maximize protective factors for DM2 in this population.

All-Cause, Cardiovascular, and Cancer Mortality in Western Alaska Native People: Western Alaska Tribal Collaborative for Health (WATCH)

OBJECTIVES We determined all-cause, cardiovascular disease (CVD), and cancer mortality in western Alaska Native people and examined agreement between death certificate information and adjudicated cause of deaths. METHODS Data from 4 cohort studies were consolidated. Death certificates and medical records were reviewed and adjudicated according to standard criteria. We compared adjudicated CVD and cancer deaths with death certificates by calculating sensitivity, specificity, predictive values, and κ statistics. RESULTS Men (n = 2116) and women (n = 2453), aged 18 to 95 years, were followed an average of 6.7 years. The major cause of death in men was trauma (25%), followed by CVD (19%) and cancer (13%). The major cause of death in women was CVD (24%), followed by cancer (19%) and trauma (8%). Stroke rates in both genders were higher than those of US Whites. Only 56% of deaths classified as CVD by death certificate were classified as CVD by standard criteria; discordance was higher among men (55%) than women (32%; κs = 0.4 and 0.7). CONCLUSIONS We found lower rates for coronary heart disease death but high rates of stroke mortality. Death certificates overestimated CVD mortality; concordance between the 2 methods is better for cancer mortality. The results point to the importance of cohort studies in this population in providing data to assist in health care planning.

Agreement Between Self-Report and Medical Record Prevalence of 16 Chronic Conditions in the Alaska EARTH Study

The gold standard for health information is the health record. Hospitalization and outpatient diagnoses provide health systems with data on which to project health costs and plan programmatic changes. Although health record information may be reliable and perceived as accurate, it may not include population-specific information and may exclude care provided outside a specific health care facility. Sole reliance on medical record information may lead to underutilization of health care services and inadequate assessment of population health status. In this study, we analyzed agreement, without assuming a gold standard, between self-reported and recorded chronic conditions in an American Indian/Alaska Native cohort. Self-reported health history was collected from 3821 adult participants of the Alaska EARTH study during 2004-2006. Participant medical records were electronically accessed and reviewed. Self-reported chronic conditions were underreported in relation to the medical record and both information sources reported the absence more reliably than the presence of conditions (across conditions, median positive predictive value = 64%, median negative predictive value = 94%). Agreement was affected by age, gender, and education. Differences between participant- and provider-based prevalence of chronic conditions demonstrate why health care administrators and policy makers should not rely exclusively on medical record–based administrative data for a comprehensive evaluation of population health.

Changes in sexual activity following substance dependence treatment

Individuals who abuse alcohol and other drugs are at increased risk for HIV/AIDS, although time of greatest risk is unclear. Although many studies have documented decreased sexual risk behaviours following substance abuse treatment, some evidence indicates that sexual risk behaviours may actually increase with sobriety. In this study, individuals involved in a substance abuse treatment programme were asked about their sexual activity for the month prior to treatment and 6 months after treatment. Results showed higher levels of sexual activity, including risky sexual activity, 6 months after discharge from treatment. This increase was found for individuals regardless of whether they were abstaining from substance use at follow-up, with highest levels of sexual activity and risky sexual activity reported by those still consuming alcohol or other drugs. These findings support the need for inclusion of HIV/AIDS prevention and educational programmes during substance abuse treatment.