Compared with standard venipuncture, the portable capillary blood collection device Tasso+ showed substantial to almost perfect concordance for measurement of abnormal liver function, a recent study showed (J Appl Lab Med 2022; doi: 10.1093/jalm/jfac127).
The researchers aimed to validate a set of liver enzymes in blood collected via Tasso+. Abnormal liver function is a feature of many common diseases. Meanwhile, venipuncture procedures have remained unchanged for decades, despite availability of systems that require very small volumes of blood for analysis and might enable home blood sample acquisition.
In a prospective biospecimens collection study involving 36 patients with abnormal liver values, the researchers evaluated Tasso+, aiming primarily to determine concordance of alanine aminotransferase (ALT) obtained via Tasso+ and compare its performance to standard venipuncture. The researchers measured 14 other analytes and surveyed patients about their experiences.
The researchers collected at least two Tasso+ samples at the time of venipuncture. One Tasso+ sample was centrifuged and shipped, while the other was refrigerated and shipped as whole blood. In all, the researchers evaluated 100 venipuncture samples, more than 50 centrifuged Tasso+ samples, and 48 Tasso+ whole blood samples.
Tasso+ centrifuged samples demonstrated concordance correlation coefficients (CCC) of more than 0.99 for ALT, alkaline phosphatase (ALP), aspartate aminotransferase (AST), and total bilirubin and more than 0.95 for albumin, chloride, enzymatic creatinine, serum glucose, magnesium, and phosphorus. Tasso+ whole blood samples showed CCC of more than 0.99 for AST, total bilirubin, and enzymatic creatinine and of more than 0.95 for AT, ALP, albumin, magnesium, and phosphorus.
Researchers said these data help to credential capillary blood collection devices as a feasible alternative approach that enables close observation of patients with liver injury at home and timely identification of hepatic deterioration. Ongoing studies aim to validate longitudinal sampling outside of the clinic.
HIGH BLOOD LIPIDS SEEN AFTER COVID-19
A recent study suggests checking blood lipids to evaluate cardiovascular risk after recovery from COVID-19 (Lancet Diabetes Endocrinol 2023; doi: 10.1016/ S2213-8587(22)00355-2).
The researchers aimed to examine the risks and 1-year burdens of incident dyslipidemia in the post-acute phase of COVID-19 among people who survived the first 30 days of SARS-CoV-2 infection.
Using U.S. Department of Veterans Affair databases, the researchers built a cohort of 51,919 participants who had a positive SARS-CoV-2 test and survived the first 30 days of infection; a noninfected contemporary control group of 2,647,654 patients; and a historical control group of 2,539,941 patients. Participants in all three cohorts had no dyslipidemia before enrollment. Control groups had no evidence of SARS-CoV-2 infection.
The researchers used inverse probability weighting to estimate the risks and 1-year burdens of incident dyslipidemia, lipid-lowering medications use, and a composite of these outcomes. They reported hazard ratios (HRs) and burden per 1,000 people at 12 months and estimated risks and burdens of incident dyslipidemia outcomes in mutually exclusive groups based on the acute care settings.
In the post-acute phase of SARS-CoV-2 infection, compared with the noninfected contemporary control group, those in the COVID-19 group had higher risks and burdens of incident dyslipidemia. These included total cholesterol greater than 200 mg/dL, LDL cholesterol greater than 130 mg/dL, triglycerides greater than 150 mg/dL, LDL cholesterol greater than 130 mg/dL, and HDL cholesterol lower than 40 mg/dL. The researchers also found increased risk and burden of incident lipid-lowering medications use. A composite of the dyslipidemia outcomes laboratory abnormality or lipid-lowering medications use yielded an HR of 1.31 (and a burden of 54.03). The degree of dyslipidemia increased with the severity of acute phase infection and was greatest in patients who needed intensive care.
An accompanying editorial says the study highlights the need to know more about how cholesterol metabolism is permanently imprinted by nutrition, infection, and inflammation.
NONCARDIAC FACTORS MAY INFLUENCE CARDIAC BIOMARKERS
A recent study highlights how noncardiac factors may influence variations in cardiac biomarkers and raises questions about the potential role of high-sensitivity cardiac troponin T (hs-cTnT) as a surrogate marker for heart failure or death in systolic blood pressure (SBP) lowering studies (Circulation 2023; doi: 10.1161/CIRCULATIONAHA.122. 059960).
Researchers found that intensive efforts to decrease SBP increased hs-cTnT, mediated by the effect of SBP lowering on reduced kidney filtration. Meanwhile, intensive SBP lowering decreased N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels, a finding explained by drop in SBP.
To test the hypothesis that intensive SBP-lowering would decrease levels of hs-cTnT and NT-proBNP, the researchers measured hs-cTnT and NT-proBNP at baseline and 1 year from stored Systolic Blood Pressure Intervention Trial (SPRINT) specimens. The researchers evaluated changes in biomarkers continuously on the log scale and according to categories (50% or greater increase, 50% or greater decrease, or less than 50% change). To assess effects of intensive SBP lowering on continuous and categorical changes in biomarker levels, the researchers used linear and multinomial logistic regression models, respectively. The researchers also assessed association between changes in biomarkers on heart failure and death using multivariable-adjusted Cox proportional hazards models.
Randomization to intensive SBP lowering, versus standard SBP management, resulted in a 3% increase in hs-cTnT levels over 1-year follow-up and a higher proportion of participants with an increase of 50% or more. However, randomization to intensive SBP lowering also led to a 10% decrease in NT-proBNP and a lower probability of a greater than 50% increase in NT- proBNP. The association of randomized treatment assignment on change in hs-cTnT was completely attenuated after accounting for changes in estimated glomerular filtration rate over follow-up, whereas the association of treatment with NT-proBNP was completely attenuated after adjusting for change in SBP. Increases in hs-cTnT and NT-proBNP from baseline to 1 year were associated with higher risk for heart failure and death, with no significant interactions by treatment assignment.
Changes in hs-cTnT levels in response to intensive SBP lowering are highly influenced by noncardiac factors, such as changes in renal filtration, the researchers noted. They added that changes in hs-cTnT in response to intensive SBP lowering may not be a reliable surrogate marker for heart failure or mortality.