They said GPs needed guidelines that address patients who have multiple diseases.
Only half of patients with type 2 diabetes achieve recommended HbA1c levels of under 7%. One reason may be the high incidence of comorbid conditions, present in half of all patients with chronic diseases, and interactions with other drugs.
Most clinical guidelines focus on single diseases and there is little to guide GPs through complex interactions between comorbidities and comedication, the researchers said.
To examine the possible impact of these interactions, a team from the University of Leuven in Belgium analysed treatment outcomes in 3,416 patients with type 2 diabetes from 55 general practices.
They analysed patients’ HbA1c levels between 1994 and 2008, comparing patients who had type 2 diabetes with those who had comorbid diseases. These included joint disorders, respiratory disease, anaemia, malignancy or depression. Many patients were also prescribed at least one NSAID, corticosteroid or antidepressant.
Patients taking drugs for diabetes were 57% more likely to have poor glucose control if they also had a joint disorder. Patients with joint disorders and respiratory disease were 34% more likely to see worsening of HbA1c. Anaemia, malignancy and depression had no effect.
Patients on corticosteroids and NSAIDs were also more likely to have poor blood glucose control.
The study authors said their findings confirmed the need for ‘comprehensive guidelines’ to care for patients with multiple diseases. ‘These guidelines should be as generic as possible but could include adapted metabolic targets discussed on the basis of patient-specific treatment goals,’ they said.
Future research must study more combinations of chronic diseases and drug therapies to improve the chance of successful diabetes treatment, they added.