Nurse Practitioner Care, Scope of Practice, and End-of-Life Outcomes for Nursing Home Residents With Dementia

Importance

Nursing home residents with Alzheimer disease and related dementias (ADRD) often receive burdensome care at the end of life. Nurse practitioners (NPs) provide an increasing share of primary care in nursing homes, but how NP care is associated with end-of-life outcomes for this population is unknown.

Objectives

To examine the association of NP care with end-of-life outcomes for nursing home residents with ADRD and assess whether these associations differ according to state-level NP scope of practice regulations.

Design, Setting, and Participants

This cohort study using fee-for-service Medicare claims included 334 618 US nursing home residents with ADRD who died between January 1, 2016, and December 31, 2018. Data were analyzed from April 6, 2015, to December 31, 2018.

Exposures

Share of nursing home primary care visits by NPs, classified as minimal (<10% of visits), moderate (10%-50% of visits), and extensive (>50% of visits). State NP scope of practice regulations were classified as full vs restrictive in 2 domains: practice authority (authorization to practice and prescribe independently) and do-not-resuscitate (DNR) authority (authorization to sign DNR orders).

Main Outcomes and Measures

Hospitalization within the last 30 days of life and death with hospice. Linear probability models with hospital referral region fixed effects controlling for resident characteristics, visit volume, and geographic factors were used to estimate whether the associations between NP care and outcomes varied across states with different scope of practice regulations.

Results

Among 334 618 nursing home decedents (mean [SD] age at death, 86.6 [8.2] years; 69.3% female), 40.5% received minimal NP care, 21.4% received moderate NP care, and 38.0% received extensive NP care. Adjusted hospitalization rates were lower for residents with extensive NP care (31.6% [95% CI, 31.4%-31.9%]) vs minimal NP care (32.3% [95% CI, 32.1%-32.6%]), whereas adjusted hospice rates were higher for residents with extensive (55.6% [95% CI, 55.3%-55.9%]) vs minimal (53.6% [95% CI, 53.3%-53.8%]) NP care. However, there was significant variation by state scope of practice. For example, in full practice authority states, adjusted hospice rates were 2.88 percentage points higher (95% CI, 1.99-3.77; P < .001) for residents with extensive vs minimal NP care, but the difference between these same groups was 1.77 percentage points (95% CI, 1.32-2.23; P < .001) in restricted practice states. Hospitalization rates were 1.76 percentage points lower (95% CI, -2.52 to -1.00; P < .001) for decedents with extensive vs minimal NP care in full practice authority states, but the difference between these same groups in restricted practice states was only 0.43 percentage points (95% CI, -0.84 to -0.01; P < .04). Similar patterns were observed in analyses focused on DNR authority.

Conclusions and Relevance

The findings of this cohort study suggest that NPs appear to be important care providers during the end-of-life period for many nursing home residents with ADRD and that regulations governing NP scope of practice may have implications for end-of-life hospitalizations and hospice use in this population.

Broad immunogenicity to prior SARS-CoV-2 strains and JN.1 variant elicited by XBB.1.5 vaccination in nursing home residents

Background

SARS-CoV-2 vaccination has reduced hospitalization and mortality for nursing home residents (NHRs). However, emerging variants coupled with waning immunity, immunosenescence, and variability of vaccine efficacy undermine vaccine effectiveness. We therefore need to update our understanding of the immunogenicity of the most recent XBB.1.5 monovalent vaccine to variant strains among NHRs.

Methods

The current study focuses on a subset of participants from a longitudinal study of consented NHRs and HCWs who have received serial blood draws to assess immunogenicity with each SARS-CoV-2 mRNA vaccine dose. We report data on participants who received the XBB.1.5 monovalent vaccine after FDA approval in Fall 2023. NHRs were classified based on whether they had an interval SARS-CoV-2 infection between their first bivalent vaccine dose and their XBB.1.5 monovalent vaccination.

Results

The sample included 61 NHRs [median age 76 (IQR 68-86), 51% female] and 28 HCWs [median age 45 (IQR 31-58), 46% female). Following XBB.1.5 monovalent vaccination, there was a robust geometric mean fold rise (GMFR) in XBB.1.5-specific neutralizing antibody titers of 17.3 (95% confidence interval [CI] 9.3, 32.4) and 11.3 (95% CI 5, 25.4) in NHRs with and without interval infection, respectively. The GMFR in HCWs was 13.6 (95% CI 8.4,22). Similarly, we noted a robust GMFR in JN.1-specific neutralizing antibody titers of 14.9 (95% CI 7.9, 28) and 6.5 (95% CI 3.3, 13.1) among NHRs with and without interval infection, and a GMFR of 11.4 (95% CI 6.2, 20.9) in HCWs. NHRs with interval SARS-CoV-2 infection had higher neutralizing antibody titers across all analyzed strains following XBB.1.5 monovalent vaccination, compared to NHRs without interval infection.

Conclusion

The XBB.1.5 monovalent vaccine significantly elevates Omicron-specific neutralizing antibody titers to XBB.1.5 and JN.1 strains in both NHRs and HCWs. This response was more pronounced in individuals known to be infected with SARS-CoV-2 since bivalent vaccination.

Impact Statement

All authors certify that this work entitled " Broad immunogenicity to prior strains and JN.1 variant elicited by XBB.1.5 vaccination in nursing home residents " is novel. It shows that the XBB.1.5 monovalent vaccine significantly elevates Omicron-specific neutralizing antibody titers in both nursing home residents and healthcare workers to XBB and BA.28.6/JN.1 strains. This work is important since JN.1 increased from less than 0.1% to 94% of COVID-19 cases from October 2023 to February 2024 in the US. This information is timely given the CDC's latest recommendation that adults age 65 and older receive a Spring 2024 XBB booster. Since the XBB.1.5 monovalent vaccine produces compelling immunogenicity to the most prevalent circulating JN.1 strain in nursing home residents, our findings add important support and rationale to encourage vaccine uptake.

Key Points

Emerging SARS-CoV-2 variants together with waning immunity, immunosenescence, and variable vaccine efficacy reduce SARS-CoV-2 vaccine effectiveness in nursing home residents.XBB.1.5 monovalent vaccination elicited robust response in both XBB.1.5 and JN.1 neutralizing antibodies in nursing home residents and healthcare workers, although the absolute titers to JN.1 were less than titers to XBB.1.5Why does this paper matter? Among nursing home residents, the XBB.1.5 monovalent SARS-CoV-2 vaccine produces compelling immunogenicity to the JN.1 strain, which represents 94% of all COVID-19 cases in the U.S. as of February 2024.

Caring for nursing home residents with dementia during the COVID-19 pandemic: Perspectives from administrators

See related Editorial by Unroe and Towsley in this issue.

COVID-19 Vaccination Among Skilled Nursing Facility Staff: Challenges and Strategies Identified by Administrators

COVID-19 vaccinations are critical for mitigating outbreaks and reducing mortality for skilled nursing facility (SNF) residents and staff, yet uptake among SNF staff varies widely and remains suboptimal. Understanding which strategies are successful for promoting staff vaccination, and examining the relationship between vaccination policies and staff retention/turnover is key for identifying best practices. We conducted repeated interviews with SNF administrators at 3-month intervals between July 2020 and December 2021 (n = 156 interviews). We found that COVID-19 vaccines were initially met with both enthusiasm and skepticism by SNF staff. Administrators reported strategies to increase staff vaccine acceptance, including incentives, one-on-one education, and less stringent personal protective equipment requirements. Federal and state vaccination mandates further promoted vaccine uptake. This combination of mandates with prioritization of the vaccine by SNFs and their leadership was successful at increasing staff vaccination acceptance, which may be critical to increase staff booster uptake from its current suboptimal levels.

Advanced practice clinician care and end-of-life outcomes for community- and nursing home-dwelling Medicare beneficiaries with dementia

INTRODUCTION

Older adults with Alzheimer's disease and related dementias (ADRD) often face burdensome end-of-life care transfers. Advanced practice clinicians (APCs)-which include nurse practitioners and physician assistants-increasingly provide primary care to this population. To fill current gaps in the literature, we measured the association between APC involvement in end-of-life care versus hospice utilization and hospitalization for older adults with ADRD.

METHODS

Using Medicare data, we identified nursing home- (N=517,490) and community-dwelling (N=322,461) beneficiaries with ADRD who died between 2016 and 2018. We employed propensity score-weighted regression methods to examine the association between different levels of APC care during their final 9 months of life versus hospice utilization and hospitalization during their final month.

RESULTS

For both nursing home- and community-dwelling beneficiaries, higher APC care involvement associated with lower hospitalization rates and higher hospice rates.

DISCUSSION

APCs are an important group of providers delivering end-of-life primary care to individuals with ADRD.

HIGHLIGHTS

For both nursing home- and community-dwelling Medicare beneficiaries with ADRD, adjusted hospitalization rates were lower and hospice rates were higher for individuals with higher proportions of APC care involvement during their final 9 months of life. Associations between APC care involvement and both adjusted hospitalization rates and adjusted hospice rates persisted when accounting for primary care visit volume.

Examination of Staffing Shortages at US Nursing Homes During the COVID-19 Pandemic

Importance

Staffing shortages have been widely reported in US nursing homes during the COVID-19 pandemic, but traditional quantitative research analyses have found mixed evidence of staffing shortfalls.

Objective

To examine whether nursing home administrator perspectives can provide context for conflicting aggregate staffing reports in US nursing homes during the COVID-19 pandemic.

Design, Setting, and Participants

In a qualitative study, convergent mixed-methods analysis integrating qualitative and quantitative data sets was used. Semistructured qualitative interviews were conducted between July 14, 2020, and December 16, 2021. Publicly available national Payroll Based Journal data were retrieved from January 1, 2020, to September 30, 2022, on 40 US nursing homes in 8 health care markets that varied by region and nursing home use patterns. Staffing and resident measures were derived from Payroll Based Journal data and compared with national trends for 15 436 US nursing homes. Nursing home administrators were recruited for interviews. Of the 40 administrators who consented to participate, 4 were lost to follow-up.

Exposure

Four repeated, semistructured qualitative interviews with participants were conducted. Interview questions focused on the changes noted during the COVID-19 pandemic in nursing homes.

Main Outcomes and Measures

Thematic description of nursing home administrator compensatory strategies to provide context for quantitative analyses on nursing home staffing levels during the COVID-19 pandemic.

Results

A total of 156 interviews were completed with 40 nursing home administrators. Administrators reported experiencing staff shortages during the COVID-19 pandemic and using compensatory strategies, such as overtime, cross-training, staff-to-resident ratio adjustments, use of agency staff, and curtailing admissions, to maintain operations and comply with minimum staffing regulations. Payroll Based Journal data measures graphed from January 1, 2020, to September 30, 2022, supported administrator reports showing that study facilities had reductions in staff hours, increased use of agency staff, and decreased resident census. Findings were similar to national trends.

Conclusions and Relevance

In this qualitative, convergent mixed-methods study, nursing home administrators reported the major staffing strain they experienced at their facilities and the strategies they used to offset staffing shortages. Their experiences provide context to quantitative analyses on aggregate nursing home census data. The short-term compensatory measures administrators used to comply with regulations and maintain operations may be detrimental to the long-term stability of this workforce.

Spillover effect of the Patient Drive Payment Model on skilled nursing facility therapy delivery among Medicare Advantage enrollees

In a multi-payer health care system, economic theory suggests that different payers can impose spillover effects on one another. This study aimed to evaluate the spillover effect of the Patient Driven Payment Model (PDPM) on Medicare Advantage (MA) enrollees, despite it being designed for Traditional Medicare (TM) beneficiaries. We applied a regression discontinuity approach by comparing therapy utilization before and after the implementation of PDPM in October 2019 focusing on patients newly admitted to skilled nursing facilities. The results showed that both TM and MA enrollees experienced a decrease in individual therapy minutes and an increase in non-individual therapy minutes. The estimated reduction in total therapy use was 9 min per day for TM enrollees and 3 min per day for MA enrollees. The effect of PDPM on MA beneficiaries varied depending on the level of MA penetration, with the smallest effect in facilities with the highest MA penetration quartile. In summary, the PDPM had directionally similar effects on therapy utilization for both TM and MA enrollees, but the magnitudes were smaller for MA beneficiaries. These results suggest that policy changes intended for TM beneficiaries may spillover to MA enrollees and should be assessed accordingly.

Durability of immunity and clinical protection in nursing home residents following bivalent SARS-CoV-2 vaccination

Background

Vaccines have substantially mitigated the disproportional impact of SARS-CoV-2 on the high morbidity and mortality experienced by nursing home residents. However, variation in vaccine efficacy, immune senescence and waning immunity all undermine vaccine effectiveness over time. The introduction of the bivalent vaccine in September 2022 aimed to counter this increasing susceptibility and consequences of breakthrough infection, however data on the durability and protection of the vaccine are limited. We evaluated the durability of immunity and protection after the first bivalent vaccination to SARS-CoV-2 in nursing home residents.

Methods

For the immunologic evaluation, community nursing home volunteers agreed to serial blood sampling before, at two weeks, three and six months after each vaccination for antibodies to spike protein and pseudovirus neutralization activity over time. Concurrent clinical outcomes were evaluated by reviewing electronic health record data from residents living in Veterans Administration managed nursing home units. Residents without recent infection but prior vaccination to SARS-CoV-2 were followed over time beginning with administration of the newly available bivalent vaccine using a target trial emulation (TTE) approach; TTE compared time to breakthrough infection, hospitalization and death between those who did and did not receive the bivalent vaccine.

Results

We evaluated antibodies in 650 nursing home residents; 452 had data available following a first monovalent booster, 257 following a second monovalent booster and 321 following a bivalent vaccine. We found a rise in BA.5 neutralization activity from the first and second monovalent boosters through the bivalent vaccination regardless of prior SARS-CoV-2 history. Titers declined at three and six months after the bivalent vaccination but generally exceeded those at three months compared to either prior boost. BA.5 neutralization titers six months after the bivalent vaccination were diminished but had detectable levels in 80% of infection-naive and 100% of prior infected individuals. TTE evaluated 5903 unique subjects, of whom 2235 received the bivalent boost. TTE demonstrated 39% or greater reduction in risk of infection, hospitalization or death at four months following the bivalent boost.

Conclusion

Immunologic results mirrored those of the TTE and suggest bivalent vaccination added substantial protection for up to six months after bivalent vaccination with notable exceptions. However, the level of protection declined over this period, and by six months may open a window of added vulnerability to infection before the next updated vaccine becomes available. We strongly agree with the CDC recommendation that those who have not received a bivalent vaccination receive that now and these results support a second bivalent booster for those at greatest risk which includes many nursing home residents.

Second monovalent SARS-CoV-2 mRNA booster restores Omicron-specific neutralizing activity in both nursing home residents and health care workers

We examined whether the second monovalent SARS-CoV-2 mRNA booster increased antibody levels and their neutralizing activity to Omicron variants in nursing home residents (NH) residents and healthcare workers (HCW). We sampled 376 NH residents and 63 HCW after primary mRNA vaccination, first and second boosters, for antibody response and pseudovirus neutralization assay against SARS-CoV-2 wild-type (WT) (Wuhan-Hu-1) strain, Omicron BA.1 and BA.5 variants. Antibody levels and neutralizing activity progressively increased with each booster but subsequently waned over 3-6 months. NH residents, both those without and with prior infection, had a robust geometric mean fold rise (GMFR) of 8.1 (95% CI 4.4, 14.8) and 7.8 (95% CI 4.8, 12.9) respectively in Omicron-BA.1 subvariant specific neutralizing antibody levels following the second booster vaccination (p < 0.001). These results support the ongoing efforts to ensure that both NH residents and HCW are up-to-date on recommended SARS-CoV-2 vaccine booster doses.

Injury-related emergency department use among assisted living residents with Alzheimer's disease and related dementias

BACKGROUND

Injuries are a leading cause of emergency department (ED) visits among older adults, and individuals with Alzheimer's disease and related dementias (ADRD) may be at particular risk. We compared injury-related ED use among assisted living (AL) residents with and without ADRD and assessed differences in the risk of injury-related ED visits among individuals with ADRD residing in ALs with memory care designation versus general AL.

METHODS

Using Medicare claims, we identified a cohort of fee-for-service beneficiaries who lived in AL in 2018 and resided in one of 20 states with site-specific information on memory care designation (n = 116,754). Outcomes included all injury-related ED visits and injury-related ED visits resulting in hospitalization in the calendar year 2018. We fit multilevel models of the association between ADRD and outcomes, adjusting for resident demographic characteristics and chronic conditions, license type characteristics, and AL characteristics, with random intercepts at the AL and license type levels. Among residents with ADRD, we examined whether memory care licensure was associated with injury-related ED visits.

RESULTS

The adjusted risk of injury-related ED use during the year was 20.1% (95% CI: 19.6%, 20.6%) for residents with ADRD compared to 16.1% for residents without ADRD (95% CI: 15.7%, 16.5%; p < 0.001). The adjusted risk of injury-related ED use ending in hospitalization was 4.9% (95% CI: 4.6%, 5.1%) for AL residents with ADRD and 3.9% for residents without ADRD (95% CI: 3.8%, 4.1%; p < 0.001). There were no significant differences in injury-related ED visits between residents with ADRD in ALs with memory care designation and residents in general AL.

CONCLUSIONS

Injury-related ED visits are common among AL residents with ADRD and residents in memory care, but residents in memory care AL experienced similar risks of injury as those in general AL. Further research should identify modifiable factors that can prevent injury among AL residents with ADRD.

Differences In Nursing Home Staff COVID-19 Testing Rates And Odds Of Vaccination Across Work Shifts

COVID-19 vaccination and regular testing of nursing home staff have been critical interventions for mitigating COVID-19 outbreaks in US nursing homes. Although implementation of testing has largely been left to nursing home organizations to coordinate, vaccination occurred through a combination of state, federal, and organization efforts. Little research has focused on structural variation in these processes. We examined whether one structural factor, the primary shift worked by staff, was associated with differences in COVID-19 testing rates and odds of vaccination, using staff-level data from a multistate sample of 294 nursing homes. In facility fixed effects analyses, we found that night-shift staff had the lowest testing rates and lowest odds of vaccination, whereas day-shift staff had the highest testing rates and odds of vaccination. These findings highlight the need to coordinate resources and communication evenly across shifts when implementing large-scale processes in nursing homes and other organizations with shift-based workforces.

SARS-CoV-2 Antibody Responses to the Ancestral SARS-CoV-2 Strain and Omicron BA.1 and BA.4/BA.5 Variants in Nursing Home Residents After Receipt of Bivalent COVID-19 Vaccine - Ohio and Rhode Island, September-November 2022

Introduction of monovalent COVID-19 mRNA vaccines in late 2020 helped to mitigate disproportionate COVID-19-related morbidity and mortality in U.S. nursing homes (1); however, reduced effectiveness of monovalent vaccines during the period of Omicron variant predominance led to recommendations for booster doses with bivalent COVID-19 mRNA vaccines that include an Omicron BA.4/BA.5 spike protein component to broaden immune response and improve vaccine effectiveness against circulating Omicron variants (2). Recent studies suggest that bivalent booster doses provide substantial additional protection against SARS-CoV-2 infection and severe COVID-19-associated disease among immunocompetent adults who previously received only monovalent vaccines (3).* The immunologic response after receipt of bivalent boosters among nursing home residents, who often mount poor immunologic responses to vaccines, remains unknown. Serial testing of anti-spike protein antibody binding and neutralizing antibody titers in serum collected from 233 long-stay nursing home residents from the time of their primary vaccination series and including any subsequent booster doses, including the bivalent vaccine, was performed. The bivalent COVID-19 mRNA vaccine substantially increased anti-spike and neutralizing antibody titers against Omicron sublineages, including BA.1 and BA.4/BA.5, irrespective of previous SARS-CoV-2 infection or previous receipt of 1 or 2 booster doses. These data, in combination with evidence of low uptake of bivalent booster vaccination among residents and staff members in nursing homes (4), support the recommendation that nursing home residents and staff members receive a bivalent COVID-19 booster dose to reduce associated morbidity and mortality (2).

Infections, Hospitalizations, and Deaths Among US Nursing Home Residents With vs Without a SARS-CoV-2 Vaccine Booster

Importance

A SARS-CoV-2 vaccine booster dose has been recommended for all nursing home residents. However, data on the effectiveness of an mRNA vaccine booster in preventing infection, hospitalization, and death in this vulnerable population are lacking.

Objective

To evaluate the association between receipt of a SARS-CoV-2 mRNA vaccine booster and prevention of infection, hospitalization, or death among nursing home residents.

Design, Setting, and Participants

This cohort study emulated sequentially nested target trials for vaccination using data from 2 large multistate US nursing home systems: Genesis HealthCare, a community nursing home operator (system 1) and Veterans Health Administration community living centers (VHA CLCs; system 2). The cohort included long-term (≥100 days) nursing home residents (10 949 residents from 202 community nursing homes and 4321 residents from 128 VHA CLCs) who completed a 2-dose series of an mRNA vaccine (either BNT162b2 [Pfizer-BioNTech] or mRNA-1273 [Moderna]) and were eligible for a booster dose between September 22 and November 30, 2021. Residents were followed up until March 8, 2022.

Exposures

Receipt of a third mRNA vaccine dose, defined as a booster dose (boosted group), or nonreceipt of a booster dose (unboosted group) on an eligible target trial date. If participants in the unboosted group received a booster dose on a later target trial date, they were included in the booster group for that target trial; thus, participants could be included in both the boosted and unboosted groups.

Main Outcomes and Measures

Test-confirmed SARS-CoV-2 infection, hospitalization, or death was followed up to 12 weeks after booster vaccination. The primary measure of estimated vaccine effectiveness was the ratio of cumulative incidences in the boosted group vs the unboosted group at week 12, adjusted with inverse probability weights for treatment and censoring.

Results

System 1 included 202 community nursing homes; among 8332 boosted residents (5325 [63.9%] female; 6685 [80.2%] White) vs 10 886 unboosted residents (6865 [63.1%] female; 8651 [79.5%] White), the median age was 78 (IQR, 68-87) years vs 78 (IQR, 68-86) years. System 2 included 128 VHA CLCs; among 3289 boosted residents (3157 [96.0%] male; 1950 [59.3%] White) vs 4317 unboosted residents (4151 [96.2%] male; 2434 [56.4%] White), the median age was 74 (IQR, 70-80) vs 74 (IQR, 69-80) years. Booster vaccination was associated with reductions in SARS-CoV-2 infections of 37.7% (95% CI, 25.4%-44.2%) in system 1 and 57.7% (95% CI, 43.5%-67.8%) in system 2. For hospitalization, reductions of 74.4% (95% CI, 44.6%-86.2%) in system 1 and 64.1% (95% CI, 41.3%-76.0%) in system 2 were observed. Estimated vaccine effectiveness for death associated with SARS-CoV-2 was 87.9% (95% CI, 75.9%-93.9%) in system 1; however, although a reduction in death was observed in system 2 (46.6%; 95% CI, -34.6% to 94.8%), this reduction was not statistically significant. A total of 45 SARS-CoV-2-associated deaths occurred in system 1 and 18 deaths occurred in system 2. For the combined end point of SARS-CoV-2-associated hospitalization or death, boosted residents in system 1 had an 80.3% (95% CI, 65.7%-88.5%) reduction, and boosted residents in system 2 had a 63.8% (95% CI, 41.4%-76.1%) reduction.

Conclusions and Relevance

In this study, during a period in which both the Delta and Omicron variants were circulating, SARS-CoV-2 booster vaccination was associated with significant reductions in SARS-CoV-2 infections, hospitalizations, and the combined end point of hospitalization or death among residents of 2 US nursing home systems. These findings suggest that administration of vaccine boosters to nursing home residents may have an important role in preventing COVID-19-associated morbidity and mortality.

Incidence and Outcomes of SARS-CoV-2 in Post-Acute Skilled Nursing Facility Care

OBJECTIVES

To examine the risk of contracting SARS-CoV-2 during a post-acute skilled nursing facility (SNF) stay and the associated risk of death.

DESIGN

Cohort study using Minimum Data Set and electronic health record data from a large multistate long-term care provider. Primary outcomes included testing positive for SARS-CoV-2 during the post-acute SNF stay, and death among those who tested positive.

SETTING AND PARTICIPANTS

The sample included all new admissions to the provider's 286 SNFs between January 1 and December 31, 2020. Patients known to be infected with SARS-CoV-2 at the time of admission were excluded.

METHODS

SARS-CoV-2 infection and mortality rates were measured in time intervals by month of admission. A parametric survival model with SNF random effects was used to measure the association of patient demographic factors, clinical characteristics, and month of admission, with testing positive for SARS-CoV-2.

RESULTS

The sample included 45,094 post-acute SNF admissions. Overall, 5.7% of patients tested positive for SARS-CoV-2 within 100 days of admission, with 1.0% testing positive within 1-14 days, 1.4% within 15-30 days, and 3.4% within 31-100 days. Of all newly admitted patients, 0.8% contracted SARS-CoV-2 and died, whereas 6.7% died without known infection. Infection rates and subsequent risk of death were highest for patients admitted during the first and third US pandemic waves. Patients with greater cognitive and functional impairment had a 1.45 to 1.92 times higher risk of contracting SARS-CoV-2 than patients with less impairment.

CONCLUSIONS AND IMPLICATIONS

The absolute risk of SARS-CoV-2 infection and death during a post-acute SNF admission was 0.8%. Those who did contract SARS-CoV-2 during their SNF stay had nearly double the rate of death as those who were not infected. Findings from this study provide context for people requiring post-acute care, and their support systems, in navigating decisions around SNF admission during the SARS-CoV-2 pandemic.

Factors Affecting SARS-CoV-2 Test Discordance in Skilled Nursing Facilities

OBJECTIVES

Reverse transcription polymerase chain reaction (PCR) and antigen tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are sometimes discordant. We evaluated the discordance between antigen and PCR tests sampled in skilled nursing facilities (SNFs) to assess the relationship of symptom presence, timing between tests, and the presence of a facility outbreak.

DESIGN

Observational study using electronic health record data.

SETTING AND PARTICIPANTS

Residents of 306 SNFs in 23 states, operated by 1 company.

METHODS

We identified all rapid antigen and PCR tests conducted in study SNFs as of January 10, 2021, and classified whether symptoms were present and whether the facility was in outbreak at time of testing. We calculated the proportions of antigen tests with discordant follow-up PCR results conducted no more than 2 days after the antigen test.

RESULTS

Of the 171,280 antigen tests in 34,437 SNF residents, 20,991 (12.3%) were followed by a PCR test within 2 days. A total of 1324 negative antigen tests were followed by a positive PCR result, representing 0.8% of all antigen tests and 6.3% of repeated antigen tests; while 337 positive antigen tests were followed by a negative PCR result, representing 0.2% of all antigen tests and 1.6% of repeated antigen tests. Discordance more often occurred when residents were symptomatic at time of antigen testing, during known facility outbreaks, and when the antigen test was compared with a PCR test done within 2 days vs 1 day.

CONCLUSIONS AND IMPLICATIONS

Overall, discordance between SARS-CoV-2 antigen and PCR tests was low. Discordance was more common when the individual was symptomatic at time of antigen testing and during facility outbreaks. This suggests that a testing strategy which couples widespread use of antigen tests with clinical thresholds to conduct follow-up confirmatory PCR testing appears to perform well in SNFs, where timely and accurate SARS-CoV-2 case identification are critical.

Association of State COVID-19 Vaccine Mandates With Staff Vaccination Coverage and Staffing Shortages in US Nursing Homes

Question

Are state COVID-19 vaccine mandates for US nursing home employees associated with staff vaccination coverage and reported staff shortages?

Findings

This cohort study of nursing homes in 38 states found that states with a vaccine mandate experienced an increase in staff vaccination coverage compared with facilities in states with no mandate and no worsening of reported staffing shortages following the mandates.

Meaning

These findings suggest that given the waning vaccine-induced immunity and low booster dose coverage among nursing home staff in many parts of the US, state mandates for booster doses may be warranted to improve and sustain vaccination coverage in nursing homes.

Importance

Several states implemented COVID-19 vaccine mandates for nursing home employees, which may have improved vaccine coverage but may have had the unintended consequence of staff departures.

Objective

To assess whether state vaccine mandates for US nursing home employees are associated with staff vaccination rates and reported staff shortages.

Design, Setting, and Participants

This cohort study performed event study analyses using National Healthcare Safety Network data from June 6, 2021, through November 14, 2021. Changes in weekly staff vaccination rates and reported staffing shortages were evaluated for nursing homes in states with mandates after the mandate announcement compared with changes in facilities in nonmandate states. An interaction between the mandates and county political leaning was considered. Data analysis was performed from February to March 2022.

Exposures

Weeks after announcement of a state’s COVID-19 vaccine mandate.

Main Outcomes and Measures

Weekly percentage of all health care staff at a nursing home who received at least 1 COVID-19 vaccine dose, and a weekly indicator of whether a nursing home reported a staffing shortage.

Results

Among 38 study-eligible states, 26 had no COVID-19 vaccine mandate for nursing home employees, 4 had a mandate with a test-out option, and 8 had a mandate with no test-out option. Ten weeks or more after mandate announcement, nursing homes in states with a mandate and no test-out option experienced a 6.9 percentage point (pp) increase in staff vaccination coverage (95% CI, −0.1 to 13.9); nursing homes in mandate states with a test-out option experienced a 3.1 pp increase (95% CI, 0.5 to 5.7) compared with facilities in nonmandate states. No significant increases were detected in the frequency of reported staffing shortages after a mandate announcement in mandate states with or without test-out options. Increases in vaccination rates in states with mandates were larger in Republican-leaning counties (14.3 pp if no test-out option; 4.3 pp with option), and there was no evidence of increased staffing shortages.

Conclusions and Relevance

The findings of this cohort study suggest that state-level vaccine mandates were associated with increased staff vaccination coverage without increases in reported staffing shortages. Vaccination increases were largest when mandates had no test-out option and were also larger in Republican-leaning counties, which had lower mean baseline vaccination rates. These findings support the use of state mandates for booster doses for nursing home employees because they may improve vaccine coverage, even in areas with greater vaccine hesitancy.

Adverse events following third dose of mRNA COVID-19 vaccination among nursing home residents who received the primary series

BACKGROUND

We sought to compare rates of adverse events among nursing home residents who received an mRNA COVID-19 vaccine booster dose with those who had not yet received their booster.

METHODS

We assessed a prospective cohort of 11,200 nursing home residents who received a primary COVID-19 mRNA vaccine series at least 6 months prior to September 22, 2021 and received a third "booster dose" between September 22, 2021 and February 2, 2022. Residents lived in 239 nursing homes operated by Genesis HealthCare, spanning 21 U.S. states. We screened electronic health records for 20 serious vaccine-related adverse events that are monitored following receipt of COVID-19 vaccination by the CDC's Vaccine Safety Datalink. We matched boosted and yet-to-be boosted residents during the same time period, comparing rates of events occurring 14 days after booster administration with those occurring 14 days prior to booster administration. To supplement previously reported background rates of adverse events, we report background rates of medical conditions among nursing home residents during 2020, before COVID-19 vaccines were administered in nursing homes. Events occurring in 2021-2022 were confirmed by physician chart review. We report unadjusted rates of adverse events and used a false discovery rate procedure to adjust for multiplicity of events tested.

RESULTS

No adverse events were reported during the 14 days post-booster. A few adverse events occurred prior to booster (ischemic stroke: 49.4 per 100,000 residents, 95% CI: 21.2, 115.7; venous thromboembolism: 9.9 per 100,000 residents, 95% CI: 1.7, 56.0), though differences in event rates pre- versus post-booster were not statistically significant (p < 0.05) after adjusting for multiple comparisons. No significant differences were detected between post-booster vaccination rates and prior year 14-day background rates of medical conditions.

CONCLUSIONS

No safety signals were detected following a COVID-19 mRNA vaccine booster dose in this large multi-state sample of nursing home residents.

Facility characteristics and costs associated with meeting proposed minimum staffing levels in skilled nursing facilities

BACKGROUND

Federal minimum nurse staffing levels for skilled nursing facilities (SNFs) were proposed in 2019 U.S. Congressional bills. We estimated costs and personnel needed to meet the proposed staffing levels, and examined characteristics of SNFs not meeting these thresholds.

METHODS

This was a cross-sectional analysis of 2019Q4 payroll data, the Hospital Wage Index, and other administrative data for 14,964 Medicare and Medicaid-certified SNFs. We examined characteristics of SNFs not meeting proposed minimum thresholds: 4.1 total nursing hours per resident day (HPRD); 0.75 registered nurse (RN) HPRD; 0.54 licensed practical nurse (LPN) HPRD; and 2.81 certified nursing assistant (CNA) HPRD. For SNFs falling below the thresholds, we calculated the additional HPRD needed, along with the associated full-time equivalent (FTE) personnel and salary costs.

RESULTS

In 2019, 25.0% of SNFs met the minimum 4.1 total nursing HPRD, while 31.0%, 84.5%, and 10.7% met the RN, LPN, and CNA thresholds, respectively. Only 5.0% met all four categories. In adjusted analyses, factors most strongly associated with SNFs not meeting the proposed minimums were: higher Medicaid census, larger bed size, for-profit ownership, higher county SNF competition; and, for RNs specifically, higher community poverty and lower Medicare census. Rural SNFs were less likely to meet all categories and this was explained primarily by county SNF competition. We estimate that achieving the proposed federal minimums across SNFs nationwide would require an estimated additional 35,804 RN, 3509 LPN, and 116,929 CNA FTEs at $7.25 billion annually in salary costs based on current wage rates and prepandemic resident census levels.

CONCLUSIONS

Achieving proposed minimum nurse staffing levels in SNFs will require substantial financial investment in the workforce and targeted support of low-resource facilities. Extensive recruitment and retention efforts are needed to overcome supply constraints, particularly in the aftermath of the COVID-19 pandemic.

Lessons for deprescribing from a nonessential medication hold policy in US nursing homes

BACKGROUND

At the height of the COVID-19 pandemic, a large nursing home chain implemented a policy to temporarily hold potentially unnecessary medications. We describe rates of held and discontinued medications after a temporary hold policy of potentially unnecessary or nonessential medications.

METHODS

This retrospective cohort study uses electronic health record (EHR) data on 3247 residents of 64 nursing homes operated by a multistate long-term care provider. Medications were documented in the electronic medication administration record. Overall medication held and discontinued incidences are reported. Hierarchical Bayesian modeling is used to determine individual probabilities for medication discontinuation within each facility.

RESULTS

In total, 3247 residents had 5297 nonessential medications held. Multivitamins were most likely to be held, followed by histamine-2 receptor antagonists, antihistamines, and statins. At the end of the hold policy, 2897 of 5297 (54%) were permanently discontinued, including probiotics (73%), histamine-2 receptor antagonists (66%), antihistamines (64%), and statins (45%). Demographics, cognitive and functional impairment were similar between residents with medications who were discontinued versus continued. For most medications, more than 50% of the variance in whether medications were discontinued was explained by facility rather than resident-level factors.

CONCLUSION

A temporary medication hold policy implemented during the CoVID-19 pandemic led to the deprescribing of a plurality of 'nonessential' medications. This type of organization-wide initiative may be an effective mechanism for altering future prescribing behaviors to reduce the use of unnecessary medications.

Association Between the Patient Driven Payment Model and Therapy Utilization and Patient Outcomes in US Skilled Nursing Facilities

Question

Was the Patient Driven Payment Model (PDPM), implemented in October 2019, associated with rehabilitation therapy utilization and health outcomes of patients admitted to skilled nursing facilities (SNFs)?

Findings

In this cross-sectional study of 201 084 patients admitted to an SNF after hip fracture between January 2018 and March 2020, those admitted post-PDPM received about 13% fewer therapy minutes than those admitted pre-PDPM, but the likelihood of rehospitalization and functional scores at discharge remained unchanged.

Meaning

Implementation of PDPM was associated with a reduction in the volume of therapy use without changes in subsequent hospitalization risk or discharge functional scores.

Importance

In October 2019, Medicare changed its skilled nursing facility (SNF) reimbursement model to the Patient Driven Payment Model (PDPM), which has modified financial incentives for SNFs that may relate to therapy use and health outcomes.

Objective

To assess whether implementation of the PDPM was associated with changes in therapy utilization or health outcomes.

Design, Setting, and Participants

This cross-sectional study used a regression discontinuity (RD) approach among Medicare fee-for-service postacute-care patients admitted to a Medicare-certified SNF following hip fracture between January 2018 and March 2020.

Exposures

Skilled nursing facility admission after PDPM implementation.

Main Outcomes and Measures

Main outcomes were individual and nonindividual (concurrent and group) therapy minutes per day, hospitalization within 40 days of SNF admission, SNF length of stay longer than 40 days, and discharge activities of daily living score.

Results

The study cohort included 201 084 postacute-care patients (mean [SD] age, 83.8 [8.3] years; 143 830 women [71.5%]; 185 854 White patients [92.4%]); 147 711 were admitted pre-PDPM, and 53 373 were admitted post-PDPM. A decrease in individual therapy (RD estimate: −15.9 minutes per day; 95% CI, −16.9 to −14.6) and an increase in nonindividual therapy (RD estimate: 3.6 minutes per day; 95% CI, 3.4 to 3.8) were observed. Total therapy use in the first week following admission was about 12 minutes per day (95% CI, −13.3 to −11.3) (approximately 13%) lower for residents admitted post-PDPM vs pre-PDPM. No consistent and statistically significant discontinuity in hospital readmission (0.31 percentage point increase; 95% CI, −1.46 to 2.09), SNF length of stay (2.7 percentage point decrease in likelihood of staying longer than 40 days; 95% CI, −4.83 to −0.54), or functional score at discharge (0.04 point increase in activities of daily living score; 95% CI, −0.19 to 0.26) was observed. Nonindividual therapy minutes were reduced to nearly zero in late March 2020, likely owing to COVID-19–related restrictions on communal activities in SNFs.

Conclusions and Relevance

In this cross-sectional study of SNF admission after PDPM implementation, a reduction of total therapy minutes was observed following the implementation of PDPM, even though PDPM was designed to be budget neutral. No significant changes in postacute outcomes were observed. Further study is needed to understand whether the PDPM is associated with successful discharge outcomes.

A systematic review of long-term care facility characteristics associated with COVID-19 outcomes

BACKGROUND/OBJECTIVES

The coronavirus disease 2019 (COVID-19) pandemic has taken a disproportionate toll on long-term care facility residents and staff. Our objective was to review the empirical evidence on facility characteristics associated with COVID-19 cases and deaths.

DESIGN

Systematic review.

SETTING

Long-term care facilities (nursing homes and assisted living communities).

PARTICIPANTS

Thirty-six empirical studies of factors associated with COVID-19 cases and deaths in long-term care facilities published between January 1, 2020 and June 15, 2021.

MEASUREMENTS

Outcomes included the probability of at least one case or death (or other defined threshold); numbers of cases and deaths, measured variably.

RESULTS

Larger, more rigorous studies were fairly consistent in their assessment of risk factors for COVID-19 outcomes in long-term care facilities. Larger bed size and location in an area with high COVID-19 prevalence were the strongest and most consistent predictors of facilities having more COVID-19 cases and deaths. Outcomes varied by facility racial composition, differences that were partially explained by facility size and community COVID-19 prevalence. More staff members were associated with a higher probability of any outbreak; however, in facilities with known cases, higher staffing was associated with fewer deaths. Other characteristics, such as Nursing Home Compare 5-star ratings, ownership, and prior infection control citations, did not have consistent associations with COVID-19 outcomes.

CONCLUSION

Given the importance of community COVID-19 prevalence and facility size, studies that failed to control for these factors were likely confounded. Better control of community COVID-19 spread would have been critical for mitigating much of the morbidity and mortality long-term care residents and staff experienced during the pandemic. Traditional quality measures such as Nursing Home Compare 5-Star ratings and past deficiencies were not consistent indicators of pandemic preparedness, likely because COVID-19 presented a novel problem requiring extensive adaptation by both long-term care providers and policymakers.

Adverse Events Following One Dose of mRNA COVID-19 Vaccination Among US Nursing Home Residents With and Without a Previous SARS-CoV-2 Infection

OBJECTIVES

To compare rates of adverse events following Coronavirus Disease 2019 (COVID-19) vaccination among nursing home residents with and without previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

DESIGN

Prospective cohort.

SETTING AND PARTICIPANTS

A total of 20,918 nursing home residents who received the first dose of messenger RNA COVID-19 vaccine from December 18, 2020, through February 14, 2021, in 284 facilities within Genesis Healthcare, a large nursing home provider spanning 24 US states.

METHODS

We screened the electronic health record for adverse events, classified by the Brighton Collaboration, occurring within 15 days of a resident's first COVID-19 vaccine dose. All events were confirmed by physician chart review. To obtain risk ratios, multilevel logistic regression model that accounted for clustering (variability) across nursing homes was implemented. To balance the probability of prior SARS-CoV-2 infection (previous positive test or diagnosis by the International Classification of Diseases, 10^th Revision, Clinical Modification) more than 20 days before vaccination, we used inverse probability weighting. To adjust for multiplicity of adverse events tested, we used a false discovery rate procedure.

RESULTS

Statistically significant differences existed between those without (n = 13,163) and with previous SARS-CoV-2 infection [symptomatic (n = 5617) and asymptomatic (n = 2138)] for all baseline characteristics assessed. Only 1 adverse event was reported among those with previous SARS-CoV-2 infection (asymptomatic), venous thromboembolism [46.8 per 100,000 residents 95% confidence interval (CI) 8.3-264.5], which was not significantly different from the rate reported for those without previous infection (30.4 per 100,000 95% CI 11.8-78.1). Several other adverse events were observed for those with no previous infection, but were not statistically significantly higher than those reported with previous infection after adjustments for multiple comparisons.

CONCLUSIONS AND IMPLICATIONS

Although reactogenicity increases with preexisting immunity, we did not find that vaccination among those with previous SARS-CoV-2 infection resulted in higher rates of adverse events than those without previous infection. This study stresses the importance of monitoring novel vaccines for adverse events in this vulnerable population.

Perceptions of COVID-19 vaccines among healthcare assistants: A national survey

Background

Limited COVID‐19 vaccination acceptance among healthcare assistants (HCAs) may adversely impact older adults, who are at increased risk for severe COVID‐19 infections. Our study objective was to evaluate the perceptions of COVID‐19 vaccine safety and efficacy in a sample of frontline HCAs, overall and by race and ethnicity.

Methods

An online survey was conducted from December 2020 to January 2021 through national e‐mail listserv and private Facebook page for the National Association of Health Care Assistants. Responses from 155 HCAs, including certified nursing assistants, home health aides, certified medical assistants, and certified medication technicians, were included. A 27‐item survey asked questions about experiences and perceptions of COVID‐19 vaccines, including how confident they were that COVID‐19 vaccines are safe, effective, and adequately tested in people of color. Multivariable regression was used to identify associations with confidence in COVID‐19 vaccines.

Results

We analyzed data from 155 completed responses. Among respondents, 23.9% were black and 8.4% Latino/a. Most respondents worked in the nursing home setting (53.5%), followed by hospitals (12.9%), assisted living (11.6%), and home care (10.3%). Respondents expressed low levels of confidence in COVID‐19 vaccines, with fewer than 40% expressing at least moderate confidence in safety (38.1%), effectiveness (31.0%), or adequate testing in people of color (27.1%). Non‐white respondents reported lower levels of confidence in adequate testing of vaccines compared to white respondents. In bivariate and adjusted models, respondents who gave more favorable scores of organizational leadership at their workplace expressed greater confidence in COVID‐19 vaccines.

Conclusion

Frontline HCAs reported low confidence in COVID‐19 vaccines. Stronger organizational leadership in the workplace appears to be an important factor in influencing HCA's willingness to be vaccinated. Action is needed to enhance COVID‐19 vaccine uptake in this important population with employers playing an important role to build vaccine confidence and trust among employees.

Racial Disparities in COVID-19 Vaccine Acceptance: Building Trust to Protect Nursing Home Staff and Residents

Vaccines are critical to protect both nursing home residents and staff from COVID-19, but some staff have expressed reservations about being vaccinated. In this brief report, we describe interventions that Genesis HealthCare—one of the largest US long-term care providers—implemented after recognizing midway through vaccinations that racial and ethnic disparities existed in vaccine uptake among employees, with black and Hispanic employees having significantly lower rates of vaccination than their peers. Specifically, Genesis engaged its Diversity, Equity, and Inclusion (DEI) Committee to identify ways to augment its already comprehensive vaccine education campaign in order to build confidence among employees from minority communities. Interventions implemented beginning in late January 2021 included adding DEI representatives to information sessions to facilitate culturally sensitive discussions; holding information sessions at all times of day and night, and inviting employees’ family members to join; increasing availability of multilingual educational materials; and featuring DEI representatives in social media campaigns. Between the end of January and beginning of March 2021, we observed statistically significant improvements in the likelihood of black and Hispanic employees being vaccinated relative to white employees, calculated as the relative risk of vaccination, suggesting a reduction in vaccination disparity. Whether these trends are directly related to the organization’s efforts, or rather reflect individuals needing longer to become comfortable with the vaccines, is difficult to discern in the absence of a formal pragmatic trial. Still, these findings support the continuation of targeted educational and engagement efforts to improve vaccine uptake among staff, and the critical need to ensure that nursing homes have ongoing access to vaccine supply to continue their vaccination programs.

SARS-CoV-2 antibody detection in skilled nursing facility residents

OBJECTIVE

To describe the frequency and timing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody detection in a convenience sample of skilled nursing facility (SNF) residents with and without confirmed SARS-CoV-2 infection.

DESIGN

Retrospective analysis of SNF electronic health records.

SETTING

Qualitative SARS-CoV-2 antibody test results were available from 81 SNFs in 16 states.

PARTICIPANTS

Six hundred and sixty nine SNF residents who underwent both polymerase chain reaction (PCR) and antibody testing for SARS-CoV-2.

MEASUREMENTS

Presence of SARS-CoV-2 antibodies following the first positive PCR test for confirmed cases, or first PCR test for non-cases.

RESULTS

Among 397 residents with PCR-confirmed infection, antibodies were detected in 4 of 7 (57.1%) tested within 7-14 days of their first positive PCR test; in 44 of 47 (93.6%) tested within 15-30 days; in 182 of 219 (83.1%) tested within 31-60 days; and in 110 of 124 (88.7%) tested after 60 days. Among 272 PCR negative residents, antibodies were detected in 2 of 9 (22.2%) tested within 7-14 days of their first PCR test; in 41 of 81 (50.6%) tested within 15-30 days; in 65 of 148 (43.9%) tested within 31-60 days; and in 9 of 34 (26.5%) tested after 60 days. No significant differences in baseline resident characteristics or symptoms were observed between those with versus without antibodies.

CONCLUSIONS

These findings suggest that vulnerable older adults can mount an antibody response to SARS-CoV-2, and that antibodies are most likely to be detected within 15-30 days of diagnosis. That antibodies were detected in a large proportion of residents with no confirmed SARS-CoV-2 infection highlights the complexity of identifying who is infected in real time. Frequent surveillance and diagnostic testing based on low thresholds of clinical suspicion for symptoms and/or exposure will remain critical to inform strategies designed to mitigate outbreaks in SNFs while community SARS-CoV-2 prevalence remains high.

Rural-urban differences in diagnostic incidence and prevalence of Alzheimer's disease and related dementias

INTRODUCTION

Understanding rural-urban variation in the diagnostic incidence and prevalence of Alzheimer's disease and related dementias (ADRD) will inform policies to improve timely diagnosis and access to supportive services for older adults in rural communities.

METHODS

Using 2008 to 2015 national claims data for fee-for-service Medicare beneficiaries (roughly 170 million person-years), we computed unadjusted and adjusted diagnostic incidence and prevalence estimates for ADRD in metropolitan, micropolitan, and rural counties, and examined differences in survival rates.

RESULTS

Risk-adjusted ADRD diagnostic incidence was higher in rural versus metropolitan counties despite lower prevalence. Among beneficiaries diagnosed with ADRD in 2008, metropolitan county residents experienced longer survival compared to residents in rural and micropolitan counties.

DISCUSSION

These data suggest that older adults in rural communities may be underdiagnosed with ADRD, and/or diagnosed at later stages of dementia. Further work is needed to develop strategies to reduce this disparity.

Medicare's New Patient Driven Payment Model Resulted In Reductions In Therapy Staffing In Skilled Nursing Facilities

Medicare's Patient Driven Payment Model (PDPM) significantly altered the way skilled nursing facilities (SNFs) are paid, removing the financial incentive to maximize the volume of therapy services delivered to patients. Using federal payroll-based staffing data, we examined the effect of the PDPM on SNF therapy and nursing staff hours. After PDPM implementation, which took effect October 1, 2019, SNFs significantly reduced their therapy staff hours. Physical therapist and occupational therapist staffing levels were reduced by 5-6 percent during October-December 2019 relative to pre-PDPM levels, and physical therapy assistant and occupational therapist assistant levels were reduced by about 10 percent. These reductions were concentrated among contracted employees and were larger in SNFs with higher shares of Medicare-eligible short-stay residents. No meaningful increases in nursing staff in response to the PDPM were found. Further research is needed to determine the effect of these therapy staff reductions on SNF patient outcomes.

Short-term impact of nursing home SARS-CoV-2 vaccinations on new infections, hospitalizations, and deaths

Objective

To compare rates of incident SARS‐CoV‐2 infection and 30‐day hospitalization or death among residents with confirmed infection in nursing homes with earlier versus later SARS‐CoV‐2 vaccine clinics.

Design

Matched pairs analysis of nursing homes that had their initial vaccine clinics between December 18, 2020, and January 2, 2021, versus between January 3, 2021, and January 18, 2021. Matched facilities had their initial vaccine clinics between 12 and 16 days apart.

Setting and Participants

Two hundred and eighty nursing homes in 21 states owned and operated by the largest long‐term care provider in the United States.

Measurements

Incident SARS‐CoV‐2 infections per 100 at‐risk residents per week; hospital transfers and/or deaths per 100 residents with confirmed SARS‐CoV‐2 infection per day, averaged over a week.

Results

The early vaccinated group included 136 facilities with 12,157 residents; the late vaccinated group included 144 facilities with 13,221 residents. After 1 week, early vaccinated facilities had a predicted 2.5 fewer incident SARS‐CoV‐2 infections per 100 at‐risk residents per week (95% CI: 1.2–4.0) compared with what would have been expected based on the experience of the late vaccinated facilities. The rates remained significantly lower for several weeks. Cumulatively over 5 weeks, the predicted reduction in new infections was 5.2 cases per 100 at‐risk residents (95% CI: 3.2–7.3). By 5 to 8 weeks post‐vaccine clinic, early vaccinated facilities had a predicted 1.1 to 3.8 fewer hospitalizations and/or deaths per 100 infected residents per day, averaged by week than expected based on late vaccinated facilities' experience for a cumulative on average difference of 5 events per 100 infected residents per day.

Conclusions

The SARS‐CoV‐2 vaccines seem to have accelerated the rate of decline of incident infections, morbidity, and mortality in this large multi‐state nursing home population.

See related editorial by Ouslander et al and related articles by Moore et al, Rudolph et al, and Domi et al. in this issue.

Risk Factors Associated With All-Cause 30-Day Mortality in Nursing Home Residents With COVID-19

IMPORTANCE

The coronavirus disease 2019 (COVID-19) pandemic has severely affected nursing homes. Vulnerable nursing home residents are at high risk for adverse outcomes, but improved understanding is needed to identify risk factors for mortality among nursing home residents.

OBJECTIVE

To identify risk factors for 30-day all-cause mortality among US nursing home residents with COVID-19.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted at 351 US nursing homes among 5256 nursing home residents with COVID-19-related symptoms who had severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection confirmed by polymerase chain reaction testing between March 16 and September 15, 2020.

EXPOSURES

Resident-level characteristics, including age, sex, race/ethnicity, symptoms, chronic conditions, and physical and cognitive function.

MAIN OUTCOMES AND MEASURES

Death due to any cause within 30 days of the first positive SARS-CoV-2 test result.

RESULTS

The study included 5256 nursing home residents (3185 women [61%]; median age, 79 years [interquartile range, 69-88 years]; and 3741 White residents [71%], 909 Black residents [17%], and 586 individuals of other races/ethnicities [11%]) with COVID-19. Compared with residents aged 75 to 79 years, the odds of death were 1.46 (95% CI, 1.14-1.86) times higher for residents aged 80 to 84 years, 1.59 (95% CI, 1.25-2.03) times higher for residents aged 85 to 89 years, and 2.14 (95% CI, 1.70-2.69) times higher for residents aged 90 years or older. Women had lower risk for 30-day mortality than men (odds ratio [OR], 0.69 [95% CI, 0.60-0.80]). Two comorbidities were associated with mortality: diabetes (OR, 1.21 [95% CI, 1.05-1.40]) and chronic kidney disease (OR, 1.33 [95%, 1.11-1.61]). Fever (OR, 1.66 [95% CI, 1.41-1.96]), shortness of breath (OR, 2.52 [95% CI, 2.00-3.16]), tachycardia (OR, 1.31 [95% CI, 1.04-1.64]), and hypoxia (OR, 2.05 [95% CI, 1.68-2.50]) were also associated with increased risk of 30-day mortality. Compared with cognitively intact residents, the odds of death among residents with moderate cognitive impairment were 2.09 (95% CI, 1.68-2.59) times higher, and the odds of death among residents with severe cognitive impairment were 2.79 (95% CI, 2.14-3.66) times higher. Compared with residents with no or limited impairment in physical function, the odds of death among residents with moderate impairment were 1.49 (95% CI, 1.18-1.88) times higher, and the odds of death among residents with severe impairment were 1.64 (95% CI, 1.30-2.08) times higher.

CONCLUSIONS AND RELEVANCE

In this cohort study of US nursing home residents with COVID-19, increased age, male sex, and impaired cognitive and physical function were independently associated with mortality. Understanding these risk factors can aid in the development of clinical prediction models of mortality in this population.

COVID-19 Mortality Rates Among Nursing Home Residents Declined From March To November 2020

Improved therapeutics and supportive care in hospitals have helped reduce mortality from COVID-19. However, there is limited evidence as to whether nursing home residents, who account for a disproportionate share of COVID-19 deaths and are often managed conservatively in the nursing home instead of being admitted to the hospital, have experienced similar mortality reductions. In this study we examined changes in thirty-day mortality rates between March and November 2020 among 12,271 nursing home residents with COVID-19. We found that adjusted mortality rates significantly declined from a high of 20.9 percent in early April to 11.2 percent in early November. Mortality risk declined for residents with both symptomatic and asymptomatic infections and for residents with both high and low clinical complexity. The mechanisms driving these trends are not entirely understood, but they may include improved clinical management within nursing homes, improved personal protective equipment supply and use, and genetic changes in the virus.

Asymptomatic and Presymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 Infection Rates in a Multistate Sample of Skilled Nursing Facilities

This cross-sectional study examines the prevalence of asymptomatic and presymptomatic severe acute respiratory syndrome coronavirus 2 infection in skilled nursing facilities.

Front-line Nursing Home Staff Experiences During the COVID-19 Pandemic

OBJECTIVE

The Coronavirus disease 2019 (COVID-19) pandemic is an unprecedented challenge for nursing homes, where staff have faced rapidly evolving circumstances to care for a vulnerable resident population. Our objective was to document the experiences of these front-line health care professionals during the pandemic.

DESIGN

Electronic survey of long-term care staff. This report summarizes qualitative data from open-ended questions for the subset of respondents working in nursing homes.

SETTING AND PARTICIPANTS

A total of 152 nursing home staff from 32 states, including direct-care staff and administrators.

METHODS

From May 11 through June 4, 2020, we used social media and professional networks to disseminate an electronic survey with closed- and open-ended questions to a convenience sample of long-term care staff. Four investigators identified themes from qualitative responses for staff working in nursing homes.

RESULTS

Respondents described ongoing constraints on testing and continued reliance on crisis standards for extended use and reuse of personal protective equipment. Administrators discussed the burden of tracking and implementing sometimes confusing or contradictory guidance from numerous agencies. Direct-care staff expressed fears of infecting themselves and their families, and expressed sincere empathy and concern for their residents. They described experiencing burnout due to increased workloads, staffing shortages, and the emotional burden of caring for residents facing significant isolation, illness, and death. Respondents cited the presence or lack of organizational communication and teamwork as important factors influencing their ability to work under challenging circumstances. They also described the demoralizing impact of negative media coverage of nursing homes, contrasting this with the heroic public recognition given to hospital staff.

CONCLUSIONS AND IMPLICATIONS

Nursing home staff described working under complex and stressful circumstances during the COVID-19 pandemic. These challenges have added significant burden to an already strained and vulnerable workforce and are likely to contribute to increased burnout, turnover, and staff shortages in the long term.

Assessment of Rural-Urban Differences in Health Care Use and Survival Among Medicare Beneficiaries With Alzheimer Disease and Related Dementia

IMPORTANCE

There is poor understanding as to how survival and health care use varies among older adults living with Alzheimer disease and related dementia (ADRD) in rural vs urban areas of the United States.

OBJECTIVE

To describe survival and trajectories of hospital, hospice, nursing home, and home health care use among rural and urban Medicare beneficiaries with ADRD in the 6 years after diagnosis.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study linked Medicare claims data from January 1, 2009, to December 31, 2016, with nursing home and home health assessment data from all US counties. A total of 555 333 Medicare fee-for-service beneficiaries newly diagnosed with ADRD in 2010 were included. A total of 424 561 individuals (76.5%) resided in metropolitan counties, 75 001 (13.5%) in micropolitan counties, and 55 771 (10.0%) in rural counties.

EXPOSURES

Rurality of beneficiary's county of residence.

MAIN OUTCOMES AND MEASURES

Number of days survived after initial ADRD diagnosis; percent of survived days per month spent in the hospital, hospice nursing home, community with home health care services, and community without home health care services.

RESULTS

A total of 555 333 Medicare beneficiaries (mean [SD] age, 82.0 [7.5] years; 345 294 women [62.2%]; 480 286 White [86.5%]) were evaluated. Compared with metropolitan county residents, rural beneficiaries were younger (mean [SD] age, 81.6 [7.6] vs 82.1 [7.5] years), were less likely to be women (34 100 [61.1%] vs 264 688 [62.3%]), were more likely to be White (50 886 [91.2%] vs 361 205 [85.1%]) and Medicaid-eligible (14 264 [25.6%] vs 71 656 [16.9%]), and had fewer preexisting chronic conditions (mean [SD], 6.9 [2.8] vs 7.4 [2.9]). Medicare beneficiaries residing in metropolitan counties survived a mean (SD) of 1183.5 (826.0) days after diagnosis. Adjusting for individual demographic and clinical characteristics, rural and micropolitan county residents survived approximately 1.5 months less than metropolitan residents. The adjusted share of survived days spent in nursing homes was 5.7 (95% CI, 4.0-7.5) percentage points higher for rural vs metropolitan residents. The adjusted share of days in hospitals was 0.7 (95% CI, -0.9 to -0.4) percentage points lower, and the share of days in community without home health care was 4.6 (95% CI, -6.1 to -3.1) percentage points lower for rural vs metropolitan county residents. There were no statistically significant differences in home health or hospice use. Similar patterns were found for micropolitan vs metropolitan residents as for rural vs metropolitan residents, although the magnitude of the differences were smaller. Differences in time spent in community and nursing homes between rural vs metropolitan beneficiaries became more pronounced with further time from diagnosis.

CONCLUSIONS AND RELEVANCE

Study results suggest that, after diagnosis, rural Medicare beneficiaries with ADRD spend more time in nursing homes and less time in the community, receive less home health care, and have shorter survival than their urban counterparts.

Variation in SARS-CoV-2 Prevalence in U.S. Skilled Nursing Facilities

OBJECTIVE

To identify county and facility factors associated with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) outbreaks in skilled nursing facilities (SNFs).

DESIGN

Cross‐sectional study linking county SARS‐CoV‐2 prevalence data, administrative data, state reports of SNF outbreaks, and data from Genesis HealthCare, a large multistate provider of post‐acute and long‐term care. State data are reported as of April 21, 2020; Genesis data are reported as of May 4, 2020.

SETTING AND PARTICIPANTS

The Genesis sample consisted of 341 SNFs in 25 states, including a subset of 64 SNFs that underwent universal testing of all residents. The non‐Genesis sample included all other SNFs (n = 3,016) in the 12 states where Genesis operates that released the names of SNFs with outbreaks.

MEASUREMENTS

For Genesis and non‐Genesis SNFs: any outbreak (one or more residents testing positive for SARS‐CoV‐2). For Genesis SNFs only: number of confirmed cases, SNF case fatality rate, and prevalence after universal testing.

RESULTS

One hundred eighteen (34.6%) Genesis SNFs and 640 (21.2%) non‐Genesis SNFs had outbreaks. A difference in county prevalence of 1,000 cases per 100,000 (1%) was associated with a 33.6 percentage point (95% confidence interval (CI) = 9.6–57.7 percentage point; P = .008) difference in the probability of an outbreak for Genesis and non‐Genesis SNFs combined, and a difference of 12.5 cases per facility (95% CI = 4.4–20.8 cases; P = .003) for Genesis SNFs. A 10‐bed difference in facility size was associated with a 0.9 percentage point (95% CI = 0.6–1.2 percentage point; P < .001) difference in the probability of outbreak. We found no consistent relationship between Nursing Home Compare Five‐Star ratings or past infection control deficiency citations and probability or severity of outbreak.

CONCLUSIONS

Larger SNFs and SNFs in areas of high SARS‐CoV‐2 prevalence are at high risk for outbreaks and must have access to universal testing to detect cases, implement mitigation strategies, and prevent further potentially avoidable cases and related complications. J Am Geriatr Soc 68:2167–2173, 2020.

See related Special Article by Ouslander et al. in this issue.

Trends In Hospitals And Skilled Nursing Facilities Sharing Medical Providers, 2008-16

Hospitals and skilled nursing facilities (SNFs) face increasing pressure to improve care coordination and reduce unnecessary readmissions. One strategy to accomplish this is to share physicians and advanced practice clinicians, so that the same providers see patients in both settings. Using 2008-16 Medicare claims, we found that as SNFs moved increasingly toward using SNF specialists, there was a steady decline in the number of facilities sharing medical providers and in the proportion of SNF primary care delivered by provider practices with both hospital and SNF clinicians (hospital-SNF practices). In SNF fixed effects analyses, we found that SNFs that increased primary care visits by hospital-SNF practices had slightly fewer readmissions, shorter lengths-of-stay, and increased successful community discharges. These findings suggest that SNFs that share medical providers with hospitals may see some benefit from that linkage, although the magnitude of the benefit may be small.

Association of Diagnosis Coding With Differences in Risk-Adjusted Short-term Mortality Between Critical Access and Non-Critical Access Hospitals

IMPORTANCE

Critical access hospitals (CAHs) provide care to rural communities. Increasing mortality rates have been reported for CAHs relative to non-CAHs. Because Medicare reimburses CAHs at cost, CAHs may report fewer diagnoses than non-CAHs, which may affect risk-adjusted comparisons of outcomes.

OBJECTIVE

To assess serial differences in risk-adjusted mortality rates between CAHs and non-CAHs after accounting for differences in diagnosis coding.

DESIGN, SETTING, AND PARTICIPANTS

Serial cross-sectional study of rural Medicare Fee-for-Service beneficiaries admitted to US CAHs and non-CAHs for pneumonia, heart failure, chronic obstructive pulmonary disease, arrhythmia, urinary tract infection, septicemia, and stroke from 2007 to 2017. The final date of follow-up was December 31, 2017.

EXPOSURE

Admission to a CAH vs non-CAH.

MAIN OUTCOMES AND MEASURES

Discharge diagnosis count including trends from 2010 to 2011 when Medicare expanded the allowable number of billing codes for hospitalizations, and combined in-hospital and 30-day postdischarge mortality adjusted for demographics, primary diagnosis, preexisting conditions, and with vs without further adjustment for Hierarchical Condition Category (HCC) score to understand the contribution of in-hospital secondary diagnoses.

RESULTS

There were 4 094 720 hospitalizations (17% CAH) for 2 850 194 unique Medicare beneficiaries (mean [SD] age, 76.3 [11.7] years; 55.5% women). Patients in CAHs were older (median age, 80.1 vs 76.8 years) and more likely to be female (58% vs 55%). In 2010, the adjusted mean discharge diagnosis count was 7.52 for CAHs vs 8.53 for non-CAHs (difference, -0.99 [95% CI, -1.08 to -0.90]; P < .001). In 2011, the CAH vs non-CAH difference in diagnoses coded increased (P < .001 for interaction between CAH and year) to 9.27 vs 12.23 (difference, -2.96 [95% CI, -3.19 to -2.73]; P < .001). Adjusted mortality rates from the model with HCC were 13.52% for CAHs vs 11.44% for non-CAHs (percentage point difference, 2.08 [95% CI, 1.74 to 2.42]; P < .001) in 2007 and increased to 15.97% vs 12.46% (difference, 3.52 [95% CI, 3.09 to 3.94]; P < .001) in 2017 (P < .001 for interaction). Adjusted mortality rates from the model without HCC were not significantly different between CAHs and non-CAHs in all years except 2007 (12.19% vs 11.74%; difference, 0.45 [95% CI, 0.12 to 0.79]; P = .008) and 2010 (12.71% vs 12.28%; difference, 0.42 [95% CI, 0.07 to 0.77]; P = .02).

CONCLUSIONS AND RELEVANCE

For rural Medicare beneficiaries hospitalized from 2007 to 2017, CAHs submitted significantly fewer hospital diagnosis codes than non-CAHs, and short-term mortality rates adjusted for preexisting conditions but not in-hospital comorbidity measures were not significantly different by hospital type in most years. The findings suggest that short-term mortality outcomes at CAHs may not differ from those of non-CAHs after accounting for different coding practices for in-hospital comorbidities.

An Illustration of SARS-CoV-2 Dissemination Within a Skilled Nursing Facility Using Heat Maps

OBJECTIVES

To illustrate dissemination and asymptomatic transmission of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) during a skilled nursing facility (SNF) outbreak.

DESIGN

Case report.

SETTING AND PARTICIPANTS

Residents of a 150‐bed SNF.

MEASUREMENTS

Heat maps generated by the SNF's infection prevention team to track staff and resident symptoms and SARS‐CoV‐2 test results to identify infection patterns.

RESULTS

The SNF experienced a severe outbreak of SARS‐CoV‐2 early in the pandemic. The initial cluster of residents with symptoms and the first confirmed case occurred on the SNF's dementia care unit. The insufficient availability and prolonged turnaround time of testing for both residents and staff at the outset of the outbreak prevented timely and accurate identification and cohorting of cases. Despite extensive other infection control measures being in place, SARS‐CoV‐2 disseminated widely through the facility within 3 weeks of the first confirmed case, resulting in significant morbidity and mortality.

CONCLUSION

Early, rapid, universal SARS‐CoV‐2 testing of both SNF residents and staff at the outset of an outbreak and then repeatedly thereafter is critical to mitigate viral transmission. This will become even more important as states relax stay‐at‐home orders and SNF staff intermingle with communities that are increasingly mobile. Increased testing will inevitably result in more staff testing positive and having to self‐quarantine at home, meaning that states must partner with SNFs and other long‐term care providers to coordinate and support strategic staffing reserves that can supplement current frontline staff. J Am Geriatr Soc 68:2174–2178, 2020.

Registered Nurse Burnout, Job Dissatisfaction, and Missed Care in Nursing Homes

OBJECTIVES

To examine the relationship between registered nurse (RN) burnout, job dissatisfaction, and missed care in nursing homes.

DESIGN

Cross-sectional secondary analysis of linked data from the 2015 RN4CAST-US nurse survey and LTCfocus.

SETTING

A total of 540 Medicare- and Medicaid-certified nursing homes in California, Florida, New Jersey, and Pennsylvania.

PARTICIPANTS

A total of 687 direct care RNs.

MEASUREMENTS

Emotional Exhaustion subscale of the Maslach Burnout Inventory, job dissatisfaction, and missed care.

RESULTS

Across all RNs, 30% exhibited high levels of burnout, 31% were dissatisfied with their job, and 72% reported missing one or more necessary care tasks on their last shift due to lack of time or resources. One in five RNs reported frequently being unable to complete necessary patient care. Controlling for RN and nursing home characteristics, RNs with burnout were five times more likely to leave necessary care undone (odds ratio [OR] = 4.97; 95% confidence interval [CI] = 2.56-9.66) than RNs without burnout. RNs who were dissatisfied were 2.6 times more likely to leave necessary care undone (OR = 2.56; 95% CI = 1.68-3.91) than RNs who were satisfied. Tasks most often left undone were comforting/talking with patients, providing adequate patient surveillance, patient/family teaching, and care planning.

CONCLUSION

Missed nursing care due to inadequate time or resources is common in nursing homes and is associated with RN burnout and job dissatisfaction. Improved work environments with sufficient staff hold promise for improving care and nurse retention. J Am Geriatr Soc 67:2065-2071, 2019.

Registered Nurse Burnout, Job Dissatisfaction, and Missed Care in Nursing Homes

OBJECTIVES

To examine the relationship between registered nurse (RN) burnout, job dissatisfaction, and missed care in nursing homes.

DESIGN

Cross-sectional secondary analysis of linked data from the 2015 RN4CAST-US nurse survey and LTCfocus.

SETTING

A total of 540 Medicare- and Medicaid-certified nursing homes in California, Florida, New Jersey, and Pennsylvania.

PARTICIPANTS

A total of 687 direct care RNs.

MEASUREMENTS

Emotional Exhaustion subscale of the Maslach Burnout Inventory, job dissatisfaction, and missed care.

RESULTS

Across all RNs, 30% exhibited high levels of burnout, 31% were dissatisfied with their job, and 72% reported missing one or more necessary care tasks on their last shift due to lack of time or resources. One in five RNs reported frequently being unable to complete necessary patient care. Controlling for RN and nursing home characteristics, RNs with burnout were five times more likely to leave necessary care undone (odds ratio [OR] = 4.97; 95% confidence interval [CI] = 2.56-9.66) than RNs without burnout. RNs who were dissatisfied were 2.6 times more likely to leave necessary care undone (OR = 2.56; 95% CI = 1.68-3.91) than RNs who were satisfied. Tasks most often left undone were comforting/talking with patients, providing adequate patient surveillance, patient/family teaching, and care planning.

CONCLUSION

Missed nursing care due to inadequate time or resources is common in nursing homes and is associated with RN burnout and job dissatisfaction. Improved work environments with sufficient staff hold promise for improving care and nurse retention. J Am Geriatr Soc 67:2065-2071, 2019.

Lower Postsurgical Mortality for Individuals with Dementia with Better-Educated Hospital Workforce

OBJECTIVES

To investigate whether care in a hospital with more nurses holding at least a Bachelor of Science in Nursing (BSN) degree is associated with lower mortality for individuals with Alzheimer's disease and related dementias (ADRD) undergoing surgery ADRD.

DESIGN

Cross-sectional data from 2006-07 Medicare claims were linked with the Multi-State Nursing Care and Patient Safety Survey of nurses in 4 states.

SETTING

Adult, nonfederal, acute care hospitals in California, Florida, New Jersey, and Pennsylvania (N=531).

PARTICIPANTS

Medicare beneficiaries aged 65 and older with and without ADRD undergoing general, orthopedic, or vascular surgery (N=353,333; ADRD, n=46,163; no ADRD, n=307,170).

MEASUREMENTS

Thirty-day mortality and failure to rescue (death after a complication).

RESULTS

Controlling for hospital, procedure, and individual characteristics, each 10% increase in the proportion of BSN nurses was associated with 4% lower odds of death (odds ratio (OR)=0.96, 95% confidence interval (CI)=0.93-0.98) for individuals without ADRD, but 10% lower odds of death (OR=0.90, 95% CI=0.87-0.94) for those with ADRD. Each 10% increase in the proportion of nurses holding a BSN degree or higher was associated with 5% lower odds of failure to rescue (OR=0.95, 95% CI=0.92-0.98) for individuals without ADRD but 10% lower odds of failure to rescue (OR=0.90, 95% CI=0.87-0.94) for those with ADRD.

CONCLUSION

Individuals undergoing surgery who have coexisting ADRD are more likely to die within 30 days of admission and die after a complication than those without ADRD. Having more BSN nurses in the hospital improves the odds of good outcomes for all individuals and has a much greater effect in individuals with ADRD.

Can hybridization cause local extinction: a case for demographic swamping of the Australian native Senecio pinnatifolius by the invasive Senecio madagascariensis?

Hybridization between native and invasive species can have several outcomes, including enhanced weediness in hybrid progeny, evolution of new hybrid lineages and decline of hybridizing species. Whether there is a decline of hybridizing species largely depends on the relative frequencies of parental taxa and the viability of hybrid progeny. Here, the individual- and population-level consequences of hybridization between the Australian native Senecio pinnatifolius and the exotic Senecio madagascariensis were investigated with amplified fragment length polymorphism (AFLP) markers, and this information was used to estimate the annual loss of viable seeds to hybridization. A high frequency (range 8.3-75.6%) of hybrids was detected in open pollinated seeds of both species, but mature hybrids were absent from sympatric populations. A hybridization advantage was observed for S. madagascariensis, where significantly more progeny than expected were sired based on proportional representation of the two species in sympatric populations. Calculations indicated that S. pinnatifolius would produce less viable seed than S. madagascariensis, if hybridization was frequency dependent and S. madagascariensis reached a frequency of between 10 and 60%. For this native-exotic species pair, prezygotic isolating barriers are weak, but low hybrid viability maintains a strong postzygotic barrier to introgression. As a result of asymmetric hybridization, S. pinnatifolius would appear to be under threat if S. madagascariensis increases numerically in areas of contact.

The effect of elevated hydrostatic pressure on the spectral absorption of deep-sea fish visual pigments

The effect of hydrostatic pressure (0.1-54 MPa, equivalent to pressures experienced by fish from the ocean's surface to depths of ca. 5,400 m) on visual pigment absorption spectra was investigated for rod visual pigments extracted from the retinae of 12 species of deep-sea fish of diverse phylogeny and habitat. The wavelength of peak absorption (lambda(max)) was shifted to longer wavelengths by an average of 1.35 nm at 40 MPa (a pressure approximately equivalent to average ocean depth) relative to measurements made at one atmosphere (ca. 0.1 MPa), but with little evidence of a change in absorbance at the lambda(max). We conclude that previous lambda(max) measurements of deep-sea fish visual pigments, made at a pressure close to 0.1 MPa, provide a good indication of lambda(max) values at higher pressures when considering the ecology of vision in the deep-sea. Although not affecting the spectral sensitivity of the animal to any important degree, the observed shift in lambda(max) may be of interest in the context of understanding opsin-chromophore interaction and spectral tuning of visual pigments.