It remains unclear whether routine diabetes screening in primary care improves cardiovascular outcomes, findings from a prospective study suggest.
Although baseline risk profiles were worse among patients with screening-detected type 2 diabetes compared with those whose diagnosis was based on clinical symptoms, risk for a composite of adverse cardiovascular outcomes — including stroke, heart attack and mortality — was the same among the two groups after seven years (9.5% vs. 10.2%, P=0.78).
This may indicate that targeted screening efforts prevented worse vascular outcomes among the higher-risk patients, study researcher Erwin P. Klein Woolthuis, MD, of Radboud University Nijmegen Medical Centre in Nijmegen, the Netherlands, and colleagues suggested in Annals of Family Medicine.
But a lack of difference in the composite primary outcome also raises questions about the utility of diabetes screening, they acknowledged.
Woothuis and colleagues analyzed data from patients at 10 family care practices participating in the Diabscreen study who were aged 45 to 75 years. Patients were enrolled from 1998 and 2005 and included 206 patients whose diagnosis was based on classic hyperglycemia symptoms (polyuria and polydipsia) or milder symptoms, including fatigue, frequent infections, or blurred vision.
Another 359 patients were diagnosed after screening based on family history of diabetes, a personal history of heart disease or gestational diabetes, obesity, hypertension or high cholesterol.
Patient’s whose diagnosis was based on clinical symptoms had higher fasting blood glucose and HbA1c levels, whereas patients in the screening group had more ischemic heart disease (12% vs. 4%; P=0.001) and nephropathy (17% vs. 7%; P=0.002), and higher systolic BP and plasma creatinine.
Both groups underwent standard diabetes care following diagnosis, but patients in the screening group achieved higher rates of glycemic control (6.8% vs. 7.1%, P=0.001) and lower insulin use (5% vs.13%, P=0.002), the researchers found.
Primary composite endpoints were no different among the two groups at seven-year follow-up (adjusted HR=0.67; 95% CI: 0.36-0.25), nor were outcomes for the following component endpoints:
- Deaths from cardiovascular disease (HR=1.88; 95% CI: 0.41- 8.57)
- Nonfatal MI (HR=0.43; 95% CI: 0.18-1.02)
- Nonfatal stroke (HR=0.68; 95% CI: 0.23-2.02)
Study limitations included lack of data on baseline HbA1c levels and patient lifestyle factors, the researchers noted.