Diabetes, Glucose Control, Glucose Lowering Medications, and Cancer Risk: A 10-year Population-based Historical Cohort (DBCA)

October 17, 2017 updated by: Sheba Medical Center

This is a large nationwide population study, with 10 year follow-up, of the effect of diabetes, metabolic control and a large number of glucose-lowering medications, on total and site-specific cancer incidence and survival.

The study is based on electronic medical records from the largest Israeli health maintenance organization in Israel, Clalit Health Services. 2,301,990 insurees age 21 years old or above at study entry, January 2002 will be included. Four study groups will be established according to the prevalence of diabetes and/or cancer on that date: neither diabetes nor cancer; prevalent diabetes but not cancer; prevalent cancer but not diabetes; both diabetes and cancer prevalence. Subjects free of diabetes at study entry will be followed for diabetes incidence, and all four groups will be followed until December 2012 for study outcomes. The cohort data file will be linked to the Israel National Cancer Registry for cancer morbidity.

We will compare, after adjustment, all and site-specific cancer rates between individuals with and without diabetes; and investigate if metabolic control, as indicated by HbA1c and blood glucose levels, is related to cancer risk. Using time-dependent Cox proportionate hazard models, we will then evaluate differences in outcomes that associate with the use of one or a combination of glucose-lowering treatments, while stratifying by those who were already diagnosed with diabetes at study entry, and those diagnosed during follow-up. Data for a large number of potential confounding variables, including BMI, plasma glucose, HbA1c, hormone replacement therapy and comorbidities will help mitigate allocation bias. The accessibility and uniformity of the healthcare provided by Clalit Health Services, as well as data on cancer screening tests, will minimize the risk of surveillance bias.

Study Overview

Status

Completed

Conditions

Detailed Description

The study was based on electronic records from the largest health maintenance organization in Israel, Clalit Health Services, which insures and provides healthcare to 55% (3.9 million) of the nation's population. All persons between 21 and 90 years and registered with Clalit on January 1, 2002 (the date of study entry), without a previous history of cancer, were included in a closed cohort that was followed until December 31 2012.

All individuals were followed for cancer incidence, which was ascertained by record linkage to the Israel National Cancer Registry, established in 1960. The registry has benefited since 1982 from a national law mandating registration of cancer, and has greater than 95% coverage of solid tumors, and approximately 85% coverage of hematologic cancers [34].

Definitions of diabetes: Incident diabetes was defined as fulfillment of at least one of the following six criteria during 2002-12: (1) diabetes recorded in the Clalit Chronic Disease Registry; (2) a physician's diagnosis of diabetes, and one plasma glucose test > 125 mg/dL within 12 months; (3) one HbA1c measurement > 6.5%; (4) 2-hour plasma glucose level during an oral glucose tolerance test ≥ 200 mg/dL; (5) 3 or more purchases of glucose-lowering medication within 12 months; (6) 2 plasma glucose measurements > 125 mg/dL within 12 months. The date of the earliest defining criterion was considered the date of diagnosis.

Prevalent diabetes was defined as being recorded with diabetes in the Clalit Chronic Disease Registry on study entry, or fulfilling criterion #5 above (information on medication use was available from 1998) before study entry.

Types of cancer: The following cancers were investigated: liver (ICD-O-3 codes C22.0 and C22.1), pancreas (C25.0-C25.9), gallbladder (C23.9-C24.9), endometrium (C54.0-C54.9, C55.9), stomach (C16.0-C16.9), kidney (C64.9, C65.9, C66.9., C68.0-C68.9), benign brain and central nervous system (C70.0-C72.9 with behavior code 0), malignant brain (C70.0-C72.9 with behavior code 3), multiple myeloma (C42.1 with relevant morphology codes), colorectum (C18.0-C21.8), non-Hodgkin lymphoma (C02.4, C09.8. C09.9, C11.1, C14.2, C37.9, C42.2, C77 and all other sites for extra-nodal Non Hodgkin's lymphoma), lung (all: C34.0-C34.9), adenocarcinoma, squamous cell), leukemia (C42.0, C42.1, C42.2 with relevant morphology codes), ovary (C56.9), bladder (C67.0-C67.9), breast (C50.0-C50.9), thyroid (C73.9) and prostate (C61.9). Apart from benign brain tumors, all cancers included in the analysis were coded as invasive (behavior code = 3).

Study Type

Observational

Enrollment (Actual)

2188669

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Israel
      • Ramat-Gan, Israel
        • The Gertner Institute for Epidemiology and Health Policy Research

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

21 years to 90 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

The cohort will include all individuals who were aged 21 years or older at study entry, January 1, 2002, and who were insured by Clalit Health Services, from one year prior to study entry, until the end of the study period, December 31, 2012, or until death, for those who did not survive until the end of follow-up.

Description

Inclusion Criteria:

  • Aged older than 21 and younger than 90 at study entry, January 1, 2002
  • Insured by Clalit Health Services

Exclusion Criteria:

  • Under age 21 at January 1, 2002
  • Over age 90 at January 1, 2002

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
diabetes free
No intervention
Diabetes prevalent
The exposure is diabetes morbidity present at study entery
Diabetes incidence
The exposure is diabetes incidence during study follow up

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Hazard ratios for all-site and site specific cancer
Time Frame: The population will be followed historically for incidence of cancer for a period of up to 11 years.
The population will be followed historically for a period of up to 11 years whichever came first, cancer incidence, mortality, age 90, or end of follow-up.
The population will be followed historically for incidence of cancer for a period of up to 11 years.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sheba Medical Center

Collaborators

European Foundation for the Study of Diabetes

Investigators

  • Principal Investigator: Rachel Dankner, MD MPH, Gertner Institute, Sheba Medical Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 1, 2012

Primary Completion (Actual)

December 1, 2015

Study Completion (Actual)

December 1, 2016

Study Registration Dates

First Submitted

February 12, 2014

First Submitted That Met QC Criteria

February 26, 2014

First Posted (Estimate)

February 27, 2014

Study Record Updates

Last Update Posted (Actual)

October 18, 2017

Last Update Submitted That Met QC Criteria

October 17, 2017

Last Verified

October 1, 2017

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • SHEBA-14-0050-RD-CTIL

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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