Black Patients at Higher Risk for Multimorbidity in Mild Cognitive Impairment

Black adults with mild cognitive impairment (MCI) are at a higher risk for hypertension, diabetes, and multiple comorbidities, according to results of a study published in Alzheimer’s & Dementia.

There are 2 subtypes of MCI: amnestic MCI, which is associated with increased risk for Alzheimer disease dementia, and nonamnestic MCI, which is associated with increased risk for vascular, frontotemporal, or Lewy body dementia.

To evaluate comorbidity trends in the MCI subtypes and the influence of race, researchers used data from the National Alzheimer’s Coordinating Center. Adults (N=8737) aged 55 years and older with normal cognitive function (n=5470), amnestic MCI (n=2620), or nonamnestic MCI (n=647) were evaluated for comorbidities by race.

[T]he study underscores racial disparities in multimorbidity, showing that Black Americans are disproportionately affected by [hypertension], [diabetes mellitus], and multimorbidity, which may contribute to their increased risk of MCI cognitive decline.

Patients in the cohorts with normal cognition, amnestic MCI, and nonamnestic MCI comprised 34.6%, 52.2%, and 46.8% men (P <.001), and were aged mean 70.2, 72.4, and 71.0 years (P <.001), respectively. Within each diagnostic group, Black individuals had a lower proportion of men (all P <.001), lower education levels (all P <.001), and higher BMI (all P <.001). In the normal cognition and amnestic MCI groups, Black individuals were also younger than White individuals (both P <.001).

In the whole sample, the most common comorbidity was hyperlipidemia (51.7%), followed by hypertension (46.4%), diabetes (9.5%), and atrial fibrillation (5.2%). Overall, 8.2% of participants had 3 comorbidities, 26.7% had 2 comorbidities, 33.1% had 1 comorbidity, and 32% had none.

Stratified by diagnostic group, comorbidity trends did not differ between the amnestic MCI and nonamnestic MCI cohorts (P =.3), whereas comorbidity rates were higher in both MCI groups compared with individuals with normal cognition (both P £.049).

Hyperlipidemia, hypertension, and diabetes were positively associated with BMI (adjusted odds ratio [aOR] range, 1.36-1.80; all P <.001), male gender (aOR range, 1.29-1.45; all P <.001), and age (aOR range, 1.02-1.07; all P <.001), and negatively associated with years of education (aOR range, 0.92-0.98; all P £.04).

In the normal cognition cohort, Black individuals were at higher risk than White individuals for hypertension (aOR, 4.29; P <.001), diabetes (aOR, 3.17; P <.001), and hyperlipidemia (aOR, 1.18; P =.001). In the amnestic MCI cohort, Black individuals were at higher risk for hypertension (aOR, 3.01; P <.001) and diabetes (aOR, 2.94; P <.001). In the nonamnestic MCI cohort, Black individuals were at an even higher risk for hypertension (aOR, 5.76; P <.001) and diabetes (aOR, 3.05; P <.001).

Risk for having comorbidities was positively associated with BMI (aOR range, 1.48-2.75; all P <.001), male gender (aOR range, 1.26-1.81; all P <.001), and age (aOR range, 1.04-1.09; all P <.001). Black individuals were more likely than White individuals to have 3 (aOR range, 5.42-8.17; all P <.001), 2 (aOR range, 2.31-4.10; all P <.001), or 1 (aOR range, 1.66-2.15; all P £.033) comorbidities, regardless of diagnosis.

Study limitations include an observational design and a racial imbalance, in which only 17.5% of participants were Black.

“Ultimately, addressing racial health disparities, promoting cardiovascular health, and improving education and health care access are vital steps toward reducing the burden of cognitive impairment and dementia in aging populations,” the authors concluded.