Physicians have long been taught that a physical examination is not complete without an assessment of whether a patient appears to be acutely or chronically ill.
But new research from St. Michael's Hospital says how sick a patient appears to be may have limited value in diagnosing their actual state of health.
"Doctors sometimes assume that they can tell at a glance whether a patient is in poor health, but it's important for physicians to realize that these impressions may be inaccurate," said Dr. Shail Rawal, the lead author of the study.
"Our findings suggest that despite its traditional role in the physical examination, a physician's assessment that a patient appears to be chronically ill has limited value in the detection of poor health status."
The findings appear in the online journal PLoS ONE.
The researchers took photographs of patients who visited five of the hospital's primary care or general internal medicine clinics and asked them to fill out a survey regarding their general physical and mental health. General internal medicine physicians and residents looked at the photos, were told how old each patient was and were then asked "do you think this patient looks chronically ill?"
The study found that a physician accurately identified that a patient was chronically ill in only 45.5 per cent of cases.
In addition, only 12 of the 126 patients were rated as "appearing chronically ill" by the majority of physicians, suggesting that there was little consensus amongst physicians on what that description means.
Dr. Stephen Hwang, a general internal medicine physician and the scientist at the hospital's Centre for Research on Inner City Health who directed the study, said he believed this was the first study to examine the performance of "appearing chronically ill" as a test for diagnosing poor health status.
The study used patient data from a previous study that found looking older does not necessarily point to poor health. That study found that a person needed to look at least 10 years older than their actual age before assumptions about their poor health could be made.