Wide geographic differences exist in treating diabetes

July 29, 2016

A large-scale observational study led by Columbia University researchers may offer new approach to studying diverse patient groups.

Around the world, the treatment for 3 common chronic diseases is proceeding toward more consistent use over time, especially in the first-line treatment of type 2 diabetes mellitus, according to a study published online in Proceedings of the National Academy of Sciences (PNAS).

Hypertension and depression have substantially less agreement, as does the second-line treatment of diabetes, according to the international observational study led by Columbia University researchers, performed in collaboration with the Observational Health Data Sciences and Informatics (OHDSI) program.

"We see substantial variation in treatment across nations and across practice types," said lead author George Hripcsak, MD, MS, Vivian Beaumont Allen Professor and chair of Biomedical Informatics at Columbia University Medical Center (CUMC), principal investigator of the OHDSI coordinating center and director of Medical Informatics Services at New York-Presbyterian/CUMC.

Using data from 250 million patient records in 4 countries, the study demonstrates the feasibility of performing large-scale observational research to obtain information about clinical practice among diverse groups of patients.

The researchers used the Observational Health Data Sciences and Informatics, or OHDSI (pronounced "odyssey") program to combine and analyze patient data from widely different sources in the United States and abroad. This enabled the researchers to collect data from 250 million patient records in 4 countries to assess patterns and variations in treatment of patients with the 3 common chronic diseases.

"Each participating site converted their data to the OHDSI data model and used the OHDSI tools set to run the identical query around the world," Hripcsak said. "A record qualified for the study if the patient had 1 of the 3 chronic diseases, had been observed without treatment for at least a year, and had been observed on treatment continually for at least 3 years."

The study showed that the vast majority of patients with diabetes worldwide are initially treated with metformin. Metformin was prescribed 75% of the time as the first medication and remained the only medication 29% of the time, thus confirming general compliance with the first-line recommendation for the treatment of diabetes from the American Association of Clinical Endocrinologists.

Although the study demonstrated good compliance with international guidelines for first-line treatment, Hripcsak says that there is less agreement with second-line and further treatment of type 2 diabetes.

Unlike with diabetes, the study found significant variation in first-line treatment of hypertension and even greater differences in the initial treatment of depression. One surprising finding was that 10% of diabetes patients, 11% of depression patients, and 24% of hypertension patients followed a treatment pathway that was shared with no one else in the study.

"In general we are seeing more consistent use of medications over time, even for diseases where there is no good agreement or understanding but there remains significant variation among countries and practice sites," said Hripcsak.

In addition to the findings related to the treatment of chronic diseases, Hripcsak says that one of the main takeaways of the study is that carrying out a large-scale international study on hundreds of millions of patient records is feasible.

"The ability to conduct observational research of a large patient population has the potential to offer insight into real-world treatment scenarios that may inform clinical trial design and ultimately, clinical practice," he said.