Predictors of Cognitive Improvement in Persons with Cognitive Impairment: A Naturalistic Study

Abstract

Introduction: Dementia has traditionally been known as a progressive illness, but with earlier detection of cognitive impairment, clinicians have observed a more variable course. The literature has suggested that depression, anxiety, apathy, psychosis, disinhibition, and nighttime behaviors may be associated with both improvement and decline in cognition but it remains inconclusive. In this study we looked at factors that may predict improvement in MMSE score at later follow up. Methods: Patients from the Brooklyn Alzheimer’s Disease Assistance Center who were evaluated for cognitive impairment were included in the study. The sample consisted of 98 people who were evaluated on their 3rd visit (mean1⁄4243 days) and 85 people evaluated at their 4th visit (mean1⁄4366 days). Mean age was 77.6 years; 77% was female; 69% were Black, 14% were White, and 13% were Latino. The outcome measure of interest was the change in MMSE score from intake to the 3rd or 4th follow up visits. The diagnoses included in the study were Dementia, Alzheimer’s type, Vascular dementia, Mixed dementia and other diagnoses. Based on preliminary analyses and a literature review, 9 predictors of outcome were identified: age, gender, Black race, general medical condition, hypertension, nighttime behavioral disturbance, receiving a cognitive enhancer, receiving an antipsychotic medication, and MMSE score at evaluation. Results: 72.9% of the clinic population were diagnosed with Dementia, Alzheimer’s type, 9.6% with Vascular dementia, 6.5% with Mixed Dementia and 11% had other diagnoses. 38% and 32% of patients had an “improved” MMSE score of 3 or more points at the 3rd and 4th visits, respectively. Variables included in the linear regression analysis of the third visit included age, gender, Black race, General Medical Health rating, history of hypertension, receiving a cognitive enhancer at the third visit, receiving an antipsychotic at the third visit and initial MMSE. Black race (t1⁄42.822, p1⁄4.007), lack of hypertension (t1⁄4-2.180, p1⁄4.034), lower MMSE score at intake (t1⁄4-2.732, p1⁄4.008) were significantly associated with improvement in MMSE score at the 3rd visit. Variables included in the linear regression analysis of the fourth visit included age, gender, Black race, General Medical Health rating, history of hypertension, receiving a cognitive enhancer at the fourth visit, receiving an antipsychotic at the fourth visit and initial MMSE. Only the MMSE at intake (t1⁄4-4.113, p1⁄4.000) was significantly associated with improvement in MMSE at the fourth visit. Conclusions: Contrary to expectations, this naturalistic study found that nearly two-fifths and one-third of dementia patients were improved at approximately 8 months and 12 months after follow-up, respectively. Black race was associated with improved MMSE score at the 3rd visit consistent with past literature that suggests Black patients may have a more variable course of cognitive decline. The effect of Black race may also explain the high percentage of patients with improved cognition in our population. In addition normal or lower blood pressure was associated with improvement in MMSE at the third visit perhaps highlighting the role of blood pressure control in preventing progression of cognitive impairment. These findings suggest, in an outpatient setting, patients with cognitive complaints may have better outcomes in terms of cognition than previously thought.