Prevalence of Independence at Home-Qualifying Beneficiaries in Traditional Medicare, 2014-2021.

Importance: The Centers for Medicare & Medicaid Services Innovation Center Independence at Home (IAH) demonstration, a test of home-based primary care operating in a value-based shared-savings payment model, ended December 2023 after a decade of consistently showing savings to Medicare. It is important to assess whether high-need, IAH-qualified beneficiaries continue to pose a growing challenge to traditional Medicare (TM) or if Medicare Advantage (MA), with programmatic features favorable to caring for this subset of the general Medicare population, can disproportionately provide such care. Objective: To examine the size and share of IAH-qualified beneficiaries in TM and MA. Design, Setting, and Participants: This cohort study used all Medicare claims data and MA encounter data for 2014 and 2021. IAH qualifying criteria were applied to the TM populations enrolled in Parts A and B in 2014 and 2021, and to MA enrollees in 2021. Growth in the number of IAH-qualified TM beneficiaries from 2014 to 2021 was calculated, and the proportions and numbers of IAH-qualified enrollees in the total 2021 TM and MA populations were compared. Data were analyzed between April and June 2023. Main Outcomes and Measures: The number and share of beneficiaries meeting IAH criteria in TM and MA; the share of TM spending among IAH-qualified beneficiaries. Results: Among 64 million Medicare beneficiaries in 2021, there were 30.55 million beneficiaries in TM with Parts A and B coverage, down from 33.82 million in 2014. The number of IAH-qualified beneficiaries in TM grew 51%, from 2.16 million to 3.27 million, while their proportionate share in TM grew 67% from 6.4% to 10.7% of TM between 2014 and 2021. IAH-qualified beneficiaries represented $155 billion in 2021 Medicare Parts A and B spending, 44% of all TM spending, up from 29% of total spending in 2014. In 2021, 2.15 million IAH-qualified beneficiaries represented 8.0% of Medicare Advantage enrollees. Combining TM and MA, 5.42 million IAH-qualified beneficiaries represented 9.3% of all Medicare beneficiaries, with 3.27 million (60.3%) being insured by TM. Conclusions and Relevance: In this cohort study of IAH-qualified Medicare beneficiaries, the share of IAH-qualified beneficiaries in TM grew between 2014 and 2021, with 60% of Medicare high-need beneficiaries accounting for 44% of TM spending. The Centers for Medicare & Medicaid Services should continue to operate value-based programs like IAH that are specifically designed for these high-needs individuals.

Effects of Transitioning to Medicare Part D on Access to Drugs for Medical Conditions among Dual Enrollees with Cancer.

OBJECTIVES: To evaluate the impact of transitioning from Medicaid to Medicare Part D drug coverage on the use of noncancer treatments among dual enrollees with cancer. METHODS: We leveraged a representative 5% national sample of all fee-for-service dual enrollees in the United States (2004-2007) to evaluate the impact of the removal of caps on the number of reimbursable prescriptions per month (drug caps) under Part D on 1) prevalence and 2) average days' supply dispensed for antidepressants, antihypertensives, and lipid-lowering agents overall and by race (white and black). RESULTS: The removal of drug caps was associated with increased use of lipid-lowering medications (days' supply 3.63; 95% confidence interval [CI] 1.57-5.70). Among blacks in capped states, we observed increased use of lipid-lowering therapy (any use 0.08 percentage points; 95% CI 0.05-0.10; and days' supply 4.01; 95% CI 2.92-5.09) and antidepressants (days' supply 2.20; 95% CI 0.61-3.78) and increasing trends in antihypertensive use (any use 0.01 percentage points; 95% CI 0.004-0.01; and days' supply 1.83; 95% CI 1.25-2.41). The white-black gap in the use of lipid-lowering medications was immediately reduced (-0.09 percentage points; 95% CI -0.15 to -0.04). We also observed a reversal in trends toward widening white-black differences in antihypertensive use (level -0.08 percentage points; 95% CI -0.12 to -0.05; and trend -0.01 percentage points; 95% CI -0.02 to -0.01) and antidepressant use (-0.004 percentage points; 95% CI -0.01 to -0.0004). CONCLUSIONS: Our findings suggest that the removal of drug caps under Part D had a modest impact on the treatment of hypercholesterolemia overall and may have reduced white-black gaps in the use of lipid-lowering and antidepressant therapies.

A Molecular and Cellular Context-Dependent Role for Ir76b in Detection of Amino Acid Taste.

Amino acid taste is expected to be a universal property among animals. Although sweet, bitter, salt, and water tastes have been well characterized in insects, the mechanisms underlying amino acid taste remain elusive. From a Drosophila RNAi screen, we identify an ionotropic receptor, Ir76b, as necessary for yeast preference. Using calcium imaging, we identify Ir76b+ amino acid taste neurons in legs, overlapping partially with sweet neurons but not those that sense other tastants. Ir76b mutants have reduced responses to amino acids, which are rescued by transgenic expression of Ir76b and a mosquito ortholog AgIr76b. Co-expression of Ir20a with Ir76b is sufficient for conferring amino acid responses in sweet-taste neurons. Notably, Ir20a also serves to block salt response of Ir76b. Our study establishes the role of a highly conserved receptor in amino acid taste and suggests a mechanism for mutually exclusive roles of Ir76b in salt- and amino-acid-sensing neurons.

Computational study of bindings of HL9, a nonapeptide fragment of human lysozyme, to HIV-1 fusion protein gp41.

HL9 is a nonapeptide fragment of human lysozyme which has been shown to have anti-HIV-1 activity in nanomolar concentration. This study aims to explain this inhibitory activity by using molecular dynamics (MD) simulation, focusing on the ectodomain of gp41, the envelope glycoprotein of HIV-1 crucial to membrane fusion. It was found that in HL9, two Trp residues separated by two others occupy the conserved hydrophobic pocket on gp41 and thus inhibit fusion in dominant-negative manner. Detailed HL9-gp41 binding interactions and free energies of binding were obtained through MD simulation and solvated interaction energies (SIE) calculation, giving a binding free energy of -8.25 kcal/mol which is in close agreement with the experimental value of -9.96 kcal/mol. Since C-helical region (C34) of gp41 also has two Trp residues separated by two others, this arrangement may be generalised and used to scan peptide library and to find those having similar manner of inhibition.

Molecular dynamics studies of human receptor molecule in hemagglutinin of 1918 and 2009 H1N1 influenza viruses.

Molecular dynamics (MD) simulations were carried out to study the behavior of human receptor molecule in the hemagglutinin (HA) of 1918 and 2009 H1N1 influenza viruses respectively. The 2009 HA model was obtained by virtually mutating the 1918 HA crystal structure based on A/Mexico City/MCIG01/2009(H1N1) segment 4 sequence. We found that human receptor molecule has no binding preference between the 2009 HA and the 1918 HA. In addition, among the four sugar moieties in the human receptor molecule, sialic acid contributes the most to the electrostatic and non-polar interaction energy during binding. Furthermore, the hydrogen bonds between sialic acid and the surrounding residues in 1918 HA are preserved in 2009 HA. We also found that the mutated residues contribute to a more favorable binding of hemagglutinin to the human receptor molecule.

Medicare spending for injured elders: are there opportunities for savings?

Claims for injury care provided to aged fee-for-service (FFS) beneficiaries cost Medicare more than $8 billion in 1999, almost 6 percent of Medicare claims spending for elders. More than one-fifth of aged FFS beneficiaries had an injury that resulted in a claim. Fractures, which were experienced by one in seventeen aged beneficiaries, were responsible far 67 percent of total injury claims expenses. Medicare could realize substantial savings if these injuries could be prevented; the program should consider underwriting effective prevention activities.