Protocol for a systematic review and individual patient data meta-analysis of prognostic factors of foot ulceration in people with diabetes: the international research collaboration for the prediction of diabetic foot ulcerations (PODUS).

BACKGROUND: Diabetes-related lower limb amputations are associated with considerable morbidity and mortality and are usually preceded by foot ulceration. The available systematic reviews of aggregate data are compromised because the primary studies report both adjusted and unadjusted estimates. As adjusted meta-analyses of aggregate data can be challenging, the best way to standardise the analytical approach is to conduct a meta-analysis based on individual patient data (IPD).There are however many challenges and fundamental methodological omissions are common; protocols are rare and the assessment of the risk of bias arising from the conduct of individual studies is frequently not performed, largely because of the absence of widely agreed criteria for assessing the risk of bias in this type of review. In this protocol we propose key methodological approaches to underpin our IPD systematic review of prognostic factors of foot ulceration in diabetes.Review questions;1. What are the most highly prognostic factors for foot ulceration (i.e. symptoms, signs, diagnostic tests) in people with diabetes?2. Can the data from each study be adjusted for a consistent set of adjustment factors?3. Does the model accuracy change when patient populations are stratified according to demographic and/or clinical characteristics? METHODS: MEDLINE and EMBASE databases from their inception until early 2012 were searched and the corresponding authors of all eligible primary studies invited to contribute their raw data. We developed relevant quality assurance items likely to identify occasions when study validity may have been compromised from several sources. A confidentiality agreement, arrangements for communication and reporting as well as ethical and governance considerations are explained.We have agreement from the corresponding authors of all studies which meet the eligibility criteria and they collectively possess data from more than 17000 patients. We propose, as a provisional analysis plan, to use a multi-level mixed model, using "study" as one of the levels. Such a model can also allow for the within-patient clustering that occurs if a patient contributes data from both feet, although to aid interpretation, we prefer to use patients rather than feet as the unit of analysis. We intend to only attempt this analysis if the results of the investigation of heterogeneity do not rule it out and the model diagnostics are acceptable. DISCUSSION: This review is central to the development of a global evidence-based strategy for the risk assessment of the foot in patients with diabetes, ensuring future recommendations are valid and can reliably inform international clinical guidelines.

Correlates of hypertension among Chippewa and Menominee Indians, the Inter-Tribal Heart Project.

OBJECTIVE: The objective of this study was to document the prevalence and control of hypertension among Chippewa and Menominee Indians who participated in the Inter-Tribal Heart Project (ITHP), and to identify the covariates of controlled hypertension in this population. DESIGN: Participants responded to an interviewer-administered questionnaire and underwent a physical examination and laboratory screening. SETTING/PARTICIPANTS: A random sample of 1376 individuals aged > or = 25 years who were active users of the Indian Health Service clinics on the Chippewa and Menominee Reservations and participated in the ITHP. RESULTS: The prevalence of hypertension (systolic blood pressure [SBP] > or = 140 mm Hg and/ or diastolic blood pressure [DBP] > or = 90 mm Hg and/or currently taking anti-hypertension medications) was 31%. Approximately 25% of individuals with hypertension were unaware of their hypertensive status. Among hypertensives, 58% reported currently using anti-hypertension medications, and only 28% had blood pressures below the recommended levels (SBP < 140 mm Hg or DBP < 90 mm Hg). CONCLUSIONS: The high prevalence of hypertension coupled with the low prevalence of controlled hypertension suggests the need to enhance and strengthen programs that target hypertension prevention and control. These programs should include pharmacologic and non-pharmacologic approaches, as well as culturally appropriate programs that incorporate beliefs held by American Indians about hypertension causation, manifestations and treatment, in an attempt to reduce this group's burden of hypertension.

Regional variation in cardiovascular disease risk factors among American Indians and Alaska Natives with diabetes.

OBJECTIVE: To compare by region risk factors for cardiovascular disease among American Indian populations with diabetes. RESEARCH DESIGN AND METHODS: Trained providers from 185 federal, urban, and tribally operated facilities reviewed the records from systematic random samples of the patients included in the local diabetes registries in the 1998 Indian Health Service (IHS) Diabetes Care and Outcomes Audit. Selected measures of cardiovascular risk were aggregated by region and adjusted to calculate regional rates for patients <45 years of age (n = 2,595) and those aged > or =45 years (n = 8,294). RESULTS: Among the younger group of patients with diabetes, the rates of elevated HbA(1c) (> or =9%) and tobacco use varied significantly among regions. High rates of obesity (78%) and elevated HbA(1c) (56%) were found in the Southwest. High rates of tobacco use (55%) but the lowest rates of elevated HbA(1c) (27%) were found in Alaska. Among patients aged > or =45 years, all measures including rates of proteinuria, cholesterol > or =200 mg/dl, and mean blood pressure > or =130/85 varied significantly among all regions. Tobacco use was highest in the Great Lakes (44%) and Great Plains (42%) regions and lowest in the Southwest (14%) and Colorado Plateau (8%) regions. Proteinuria was found most frequently in the Southwest (35%), Colorado Plateau (30%), and Pacific regions (35%). Older individuals with diabetes were more likely than younger individuals to have proteinuria and blood pressure > or =130/85. CONCLUSIONS: American Indians and Alaska Natives with diabetes carry a large burden of potentially modifiable cardiovascular risk factors, but there is significant regional variation.