Does impairment of higher level functional capacity (intellectual, social, and instrumental activities of daily living such as cooking, cleaning, shopping) predict stroke in patients who are independent in basic ADLs? Should we probe as deeply into our patients’ higher level functional capacity as we do into their past medical history? The authors of this study address these important questions in a study of 1500 Japanese patients over age 60. These patients were independent for basic ADLs, and had not had a prior stroke.
After following the patients for about 10 years, the authors found that 191 of 1493 developed a first-time stroke. As expected, age played a role: those with impaired higher level functional capacity were older than those with normal capacity, and those who had strokes were older than those who did not. Overall TMIG-IC score (measurement of higher level functional capacity) was associated with significantly higher probability of developing stroke overall in multivariate analysis. The intellectual activity subscore was the only subscore which remained significant for the overall group. When the group was stratified by age, sex, and hypertension, the intellectual activity subscore was significantly associated with stroke in women only. Social role was significantly associated with stroke in those patients 75 years or older.
It is important to ask if the association is causative – or whether there are common risk factors for stroke as well as impairment in higher level functional capacity. In this study, the association persisted after adjusting for age and risk factors. The authors suggest that higher level functional impairment may represent early cerebrovascular disease, such as silent strokes. Determining the degree of white matter disease and correlating with higher level functional status would be the logical next step to follow this study. Determining baseline function, including higher level functional capacity, is useful and may help predict stroke. It would be interesting to compare the post-stroke level of independence of stroke patients with and without baseline higher level functional impairment. I suspect that those with higher level functional impairment, even if they were independent for basic ADLs, would have more significant post-stroke disability after adjusting for location and size of stroke. Lower cognitive reserve may portend a more protracted course and more difficulty rehabilitating from a stroke. Having data on a patient’s baseline status would be helpful in predicting stroke occurrence (shown in this study) and possibly predicting outcomes post-stroke.
