Matthew T Mefford1,2, Robert S Rosenson3, Mary Cushman4, Michael E Farkouh5, Leslie A McClure6, Virginia G Wadley7, Marguerite R Irvin1,2, Vera Bittner7, Monika M Safford8, Ransi Somaratne9, Keri L Monda9, Paul Muntner1,2, Emily B Levitan10,2. 1. Department of Epidemiology (M.T.M., M.R.I., P.M., E.B.L.). 2. University of Alabama at Birmingham (M.T.M., M.R.I., P.M., E.B.L.). 3. Icahn School of Medicine at Mount Sinai, Mount Sinai Heart, New York, NY (R.S.R.). 4. Division of Hematology/Oncology, Department of Medicine, Larner College of Medicine at the University of Vermont, Burlington (M.C.). 5. Peter Munk Cardiac Centre and the Heart and Stroke Richard Lewar Centre, University of Toronto, Ontario, Canada (M.E.F.). 6. Department of Epidemiology and Biostatistics, Drexel University, Philadelphia, PA (L.A.M.). 7. Department of Medicine (V.G.W., V.B.). 8. Weill Cornell Medicine, New York, NY (M.M.S.). 9. Center for Observational Research, Amgen Inc, Thousand Oaks, CA (R.S., K.L.M.). 10. Department of Epidemiology (M.T.M., M.R.I., P.M., E.B.L.) elevitan@uab.edu.
Abstract
BACKGROUND: Despite concerns about adverse neurocognitive events raised by prior trials, pharmacological PCSK9 (proprotein convertase subtilisin/kexin type-9) inhibition was not associated with neurocognitive effects in a recent phase 3 randomized trial. PCSK9 loss-of-function (LOF) variants that result in lifelong exposure to lower levels of low-density lipoprotein cholesterol can provide information on the potential long-term effects of lower low-density lipoprotein cholesterol on neurocognitive impairment and decline. METHODS: We investigated the association between PCSK9 LOF variants and neurocognitive impairment and decline among black REGARDS study (Reasons for Geographic and Racial Differences in Stroke) participants with (n=241) and without (n=10 454) C697X or Y142X LOF variants. Neurocognitive tests included the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) battery (Word List Learning, World List Delayed Recall, Semantic Animal Fluency) and Six-Item Screener (SIS) assessments, administered longitudinally during follow-up. Neurocognitive impairment was defined as a score ≥1.5 SD below age, sex, and education-based stratum-specific means on 2 or 3 CERAD assessments or, separately, a score <5 on any SIS assessment at baseline or during follow-up. Neurocognitive decline was assessed using standardized continuous scores on individual neurocognitive tests. RESULTS: The mean sample age was 64 years (SD, 9), 62% were women, and the prevalence of neurocognitive impairment at any assessment was 6.3% by CERAD and 15.4% by SIS definitions. Adjusted odds ratios for neurocognitive impairment for participants with versus without PCSK9 LOF variants were 1.11 (95% confidence interval [CI], 0.58-2.13) using the CERAD battery and 0.89 (95% CI, 0.61-1.30) using the SIS assessment. Standardized average differences in individual neurocognitive assessment scores over the 5.6-year (range, 0.1-9.1) study period ranged between 0.07 (95% CI, -0.06 to 0.20) and -0.07 (95% CI, -0.18 to 0.05) among participants with versus without PCSK9 LOF variants. Patterns of neurocognitive decline were similar between participants with and without PCSK9 LOF variants (all P>0.10). Odds ratios for neurocognitive impairment per 20 mg/dL low-density lipoprotein cholesterol decrements were 1.02 (95% CI, 0.96-1.08) and 0.99 (95% CI, 0.95-1.02) for the CERAD and SIS definitions of impairment, respectively. CONCLUSIONS: These results suggest that lifelong exposure to low PCSK9 levels and cumulative exposure to lower levels of low-density lipoprotein cholesterol are not associated with neurocognitive effects in blacks.
BACKGROUND: Despite concerns about adverse neurocognitive events raised by prior trials, pharmacological PCSK9 (proprotein convertase subtilisin/kexin type-9) inhibition was not associated with neurocognitive effects in a recent phase 3 randomized trial. PCSK9 loss-of-function (LOF) variants that result in lifelong exposure to lower levels of low-density lipoprotein cholesterol can provide information on the potential long-term effects of lower low-density lipoprotein cholesterol on neurocognitive impairment and decline. METHODS: We investigated the association between PCSK9 LOF variants and neurocognitive impairment and decline among black REGARDS study (Reasons for Geographic and Racial Differences in Stroke) participants with (n=241) and without (n=10 454) C697X or Y142X LOF variants. Neurocognitive tests included the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) battery (Word List Learning, World List Delayed Recall, Semantic Animal Fluency) and Six-Item Screener (SIS) assessments, administered longitudinally during follow-up. Neurocognitive impairment was defined as a score ≥1.5 SD below age, sex, and education-based stratum-specific means on 2 or 3 CERAD assessments or, separately, a score <5 on any SIS assessment at baseline or during follow-up. Neurocognitive decline was assessed using standardized continuous scores on individual neurocognitive tests. RESULTS: The mean sample age was 64 years (SD, 9), 62% were women, and the prevalence of neurocognitive impairment at any assessment was 6.3% by CERAD and 15.4% by SIS definitions. Adjusted odds ratios for neurocognitive impairment for participants with versus without PCSK9 LOF variants were 1.11 (95% confidence interval [CI], 0.58-2.13) using the CERAD battery and 0.89 (95% CI, 0.61-1.30) using the SIS assessment. Standardized average differences in individual neurocognitive assessment scores over the 5.6-year (range, 0.1-9.1) study period ranged between 0.07 (95% CI, -0.06 to 0.20) and -0.07 (95% CI, -0.18 to 0.05) among participants with versus without PCSK9 LOF variants. Patterns of neurocognitive decline were similar between participants with and without PCSK9 LOF variants (all P>0.10). Odds ratios for neurocognitive impairment per 20 mg/dL low-density lipoprotein cholesterol decrements were 1.02 (95% CI, 0.96-1.08) and 0.99 (95% CI, 0.95-1.02) for the CERAD and SIS definitions of impairment, respectively. CONCLUSIONS: These results suggest that lifelong exposure to low PCSK9 levels and cumulative exposure to lower levels of low-density lipoprotein cholesterol are not associated with neurocognitive effects in blacks.
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