Health care professionals are currently trying to learn more about the connection between diabetes and cancer, including how many diabetes patients are also dealing with a cancer diagnosis. A recent study published in the journal of the European Association for the Study of Diabetes Diabetologia has revealed that diabetes patients who are diagnosed with cancer often struggle with adhering to their diabetes medication.

"This study revealed that the medication adherence among users of GLDs was influenced by cancer diagnosis,” the research team said in a statement. “Although the impact of cancer was more pronounced among cancers with a worse prognosis and among those with more advanced cancer stages, the difference in prognosis associated with these cancers seemed to only partly explain the impact of cancer on medication adherence.”

Researchers from the Netherlands Comprehensive Cancer Organisation and the School of Public Health at University of Alberta gathered data from 3,281 diabetes patients who were also diagnosed with cancer and 12,891 diabetes patients who were not diagnosed with cancer. Participants were enrolled in the Eindhoven Cancer Registry-PHARMO Database Network and had been prescribed glucose lowering drugs at the time of the study.

Adherence to a medication regimen was gauged using the Medication Possession Ratio (MPR), which represents the amount of medication a patient has in his possession over the course of a month. A 10 percent decline in MPR means the patient did not take his medication for three days out of a 30-day month. Before cancer diagnoses, the MPR increased each month by 0.10 percent.

Immediately following cancer diagnoses, MPR among patients dropped significantly by 6.3 percent and continued to drop by 0.20 percent each month after the diagnosis was made. The research team also broke down drops in MPR by types of cancer diagnoses. For example, the largest drops in MPR following cancer diagnoses were between 11 and 15 percent among those with gastrointestinal and pulmonary cancers as well as any patient with stage IV cancer.

“The decline in adherence seen among users of GLDs with cancer might negatively impact survival and (partly) explain the established association between diabetes, cancer, and mortality. In future studies, the reason for the decline in MPR needs to be further elucidated among the different cancer types — is it the patient who prioritises the fight against cancer or the advice of the physician to stop the treatment?"

According to the American Diabetes Association, type 2 diabetes and certain cancers share some risk factors, including age, gender, race/ethnicity, overweight, physical inactivity, smoking, and alcohol. Researchers from this study found that diabetes patients stopping their medication following a cancer diagnosis was not the result of a weakened will to live. Instead, they explain that certain types of cancers affecting diabetes medication adherence shows that it is more likely due to hypoglycemic events caused by cancer and intolerable oral intake of drugs.

Source: Diabetologia. 2015.