Nirmatrelvir-Ritonavir and COVID-19 Mortality and Hospitalization Among Patients With Vulnerability to COVID-19 Complications

Importance

Postmarket analysis of individuals who receive nirmatrelvir and ritonavir (Paxlovid [Pfizer]) is essential because they differ substantially from individuals included in published clinical trials.

Objective

To examine the association of nirmatrelvir and ritonavir with prevention of death or admission to hospital in individuals with different risks of complications from COVID-19 infection.

Design, Setting, and Participants

This is a cohort study of adult patients in British Columbia, Canada, between February 1, 2022, and February 3, 2023. Patients were eligible if they belonged to 1 of 4 higher-risk groups of individuals who received priority for COVID-19 vaccination. Two groups included clinically extremely vulnerable (CEV) people who were severely (CEV1) or moderately immunocompromised (CEV2). CEV3 individuals were not immunocompromised but had medical conditions associated with a high risk for complications from COVID-19. A fourth expanded eligibility (EXEL) group was added to allow wider access to nirmatrelvir and ritonavir for certain other higher-risk individuals who were not in a CEV group, such as those older than 70 years who were unvaccinated.

Exposures

Patients with COVID-19 who received nirmatrelvir and ritonavir were matched to patients in the same vulnerability group; who were of the same sex, age, and propensity score for nirmatrelvir and ritonavir treatment; and who were also infected within 1 month of the individual treated with nirmatrelvir and ritonavir.

Main Outcomes and Measures

The primary outcome was death from any cause or emergency hospitalization with COVID-19 within 28 days.

Results

There were 6866 individuals included in the study, of whom 3888 (56.6%) were female and whose median (IQR) age was 70 (57-80) years. Compared with unexposed controls, treatment with nirmatrelvir and ritonavir was associated with statistically significant relative reductions in the primary outcome in the CEV1 group (560 patients; risk difference [RD], -2.5%, 95% CI, -4.8% to -0.2%) and the CEV2 group (2628 patients; RD, -1.7%; 95% CI, -2.9% to -0.5%). In the CEV3 group, the RD was -1.3%, but the findings were not statistically significant (2100 patients; 95% CI, -2.8% to 0.1%). In the EXEL group, treatment was associated with higher risk of the outcome (RD, 1.0%), but the findings were not statistically significant (1578 patients; 95% CI, -0.9% to 2.9%).

Conclusions and Relevance

In this cohort study of 6866 individuals in British Columbia, nirmatrelvir and ritonavir treatment was associated with reduced risk of COVID-19 hospitalization or death in CEV individuals, with the greatest benefit observed in severely immunocompromised individuals. No reduction in the primary outcome was observed in lower-risk individuals, including those aged 70 years or older without serious comorbidities.

COVID-19 hospitalisations in immunocompromised individuals in the Omicron era: a population-based observational study using surveillance data in British Columbia, Canada

Background

People with immune dysfunction are at higher risk of severe outcomes from COVID-19 infection, but relatively little epidemiologic information is available for mostly vaccinated population in the Omicron era. This population-based study compared relative risk of breakthrough COVID-19 hospitalisation among vaccinated people identified as clinically extremely vulnerable (CEV) vs non-CEV individuals before treatment became more widely available.

Methods

COVID-19 cases and hospitalisations reported to the British Columbia Centre for Disease Control (BCCDC) between January 7, 2022 and March 14, 2022 were linked with data on their vaccination and CEV status. Case hospitalisation rates were estimated across CEV status, age groups and vaccination status. For vaccinated individuals, risk ratios for breakthrough hospitalisations were calculated for CEV and non-CEV populations matched on sex, age group, region, and vaccination characteristics.

Findings

Among CEV individuals, a total of 5591 COVID-19 reported cases were included, among which 1153 were hospitalized. A third vaccine dose with mRNA vaccine offered additional protection against severe illness in both CEV and non-CEV individuals. However, 2- and 3-dose vaccinated CEV population still had a significantly higher relative risk of breakthrough COVID-19 hospitalisation compared with non-CEV individuals.

Interpretation

Vaccinated CEV population remains a higher risk group in the context of circulating Omicron variant and may benefit from additional booster doses and pharmacotherapy.

Funding

BC Centre for Disease Control and Provincial Health Services Authority.

Reduced fixed dose tocilizumab 400 mg IV compared to weight-based dosing in critically ill patients with COVID-19: A before-after cohort study

Background

Interleukin-6 inhibitors reduce mortality in severe COVID-19. British Columbia began using tocilizumab 8 mg/kg (maximum 800 mg) in January 2021 in critically ill patients with COVID-19, but due to drug shortages, decreased dosing to 400 mg IV fixed dose in April 2021. The aims of this study were twofold: to compare physiological responses and clinical outcomes of these two strategies, and examine the cost-effectiveness of treating all patients with 400 mg versus half the patients with 8 mg/kg and the other half without tocilizumab.

Methods

This was a single-centre, before-after cohort study of critically ill COVID-19 patients treated with tocilizumab, and a control cohort treated with dexamethasone only. Physiological responses and clinical outcomes were compared between patients receiving both doses of tocilizumab and those receiving dexamethasone only. We built a decision tree model to examine cost-effectiveness.

Findings

152 patients were included; 40 received tocilizumab 8 mg/kg, 59 received 400 mg and 53 received dexamethasone only. Median CRP fell from 103 mg/L to 5.2 mg/L, 96 mg/L to 6.8 mg/L and from 81.3 mg/L to 48 mg/L in the 8 mg/kg, 400 mg tocilizumab, and dexamethasone only groups, respectively. 28-day mortality was 5% (n=2) vs 8% (n=5) vs 13% (n=7), with no significant difference in all pair-wise comparison. At an assumed willingness-to-pay threshold of $50,000 Canadian per life-year, utilizing 400 mg for all patients rather than 8 mg/kg for half the patients is cost-effective in 51.6% of 10,000 Monte Carlo simulations.

Interpretation

Both doses of tocilizumab demonstrated comparable reduction of inflammation with similar 28-day mortality. Without consideration of equity, the net monetary benefits of providing 400 mg tocilizumab to all patients are comparable to 8 mg/kg to half the patients. In the context of ongoing drug shortages, fixed-dose 400 mg tocilizumab may be a practical, feasible and economical option.

Funding

This work was supported by a gift donation from Hsu & Taylor Family to the VGH Foundation, and the Yale Bernard G. Forget Scholarship.

20 Evaluation of Compliance with the 2017 Canadian Pediatric Society (CPS) Position Statement for the Management of Newborns at Risk for Early-Onset Sepsis (EOS): A Retrospective Cohort Study

Background

Due to the high mortality and non-specific clinical presentation, clinicians often empirically treat newborns at risk of early-onset sepsis (EOS). Recently, the Canadian Pediatric Society (CPS) published updated recommendations that promote a more judicious approach to EOS management.

Objectives

To examine the compliance with the CPS position statement at a tertiary perinatal site.

Design/Methods

A retrospective chart review was conducted between Jan 1 – Jun 30, 2018. Newborns were categorized into 5 groups, depending on the number of EOS risk factors. Management strategies were assessed against the CPS recommendations to establish the rate of non-compliance. The reason for non-compliance, readmission rate and rate of culture-positive EOS were also examined. Results were expressed using descriptive statistics. A Chi-squared test was conducted to assess the association between the readmission rate and initial management.

Results

The total non-compliance rate was 47%. This was mostly due to inappropriate investigations in lower EOS risk groups [3 (71%) and 4 (94%)] and withholding antibiotics in groups with more risk factors [1 (43%) and 2 (67%)]. The rate of readmission for a septic work-up was low (<2%), and no newborns had culture-positive EOS. There was no significant association between the readmission rate and initial management (p=0.13).

Conclusion

Although the rate of non-compliance to the 2017 CPS recommendations was high, no neonates had culture-positive EOS, suggesting that our management strategies may be too aggressive. An initial observational period for newborns at lower EOS risk (groups 3 and 4) may warrant consideration for future quality improvement initiatives.

Evaluation of compliance with the 2017 Canadian Paediatric Society Position Statement for the management of newborns at risk for early-onset sepsis: A retrospective cohort study

Introduction

Due to the nonspecific clinical presentation, clinicians often empirically treat newborns at risk of early-onset sepsis (EOS). Recently, the Canadian Paediatric Society (CPS) published updated recommendations that promote a more judicious approach to EOS management.

Objective

To examine the compliance with the CPS statement at a tertiary perinatal site and characterize the types of deviations.

Methods

A retrospective chart review was conducted for all term and late pre-term newborns at risk for sepsis, between January 1 and June 30, 2018. The prevalence of newborns with EOS risk factors was measured during the first month. Management strategies for eligible newborns during the 6-month period were compared to the CPS recommendations to establish the rate of noncompliance. The type of noncompliance, readmission rate, and rate of culture-positive EOS were examined.

Results

In the first month, 29% (66 of 228) of newborns had EOS risk factors. Among the 100 newborns born in the 6-month period for whom the CPS recommendations apply, 47 (47%) received noncompliant management. Of those, 51% (N=24) had inappropriately initiated investigations, 17% (N=8) had inappropriate antibiotics, and 32% (N=15) had both. The rate of readmission for a septic workup was 1.6% (N= 2). None had culture-positive sepsis while admitted.

Conclusion

A large proportion of term and late preterm newborns (29%) had EOS risk factors, but none had culture-confirmed EOS. The rate of noncompliance with the CPS recommendations was high (47%), mainly due to overzealous management. Future initiatives should aim at increasing compliance, particularly in newborns at lower EOS risk.

458. Diagnostic Accuracy and Management of Suspected Moderate to Severe Cellulitis Referred to an Infectious Diseases Outpatient Parenteral Antibiotic Clinic: A Prospective Cross-Sectional Study

Background

Moderate to severe cellulitis is a common reason for presentation to the emergency department and administration of intravenous antibiotics. Misdiagnosis of cellulitis occurs frequently as the disease can masquerade as a wide variety of noninfectious and infectious problems. There are currently no studies evaluating the impact of infectious diseases physicians on the diagnostic accuracy and management of cellulitis referred to an outpatient parenteral antibiotic clinic from the emergency department. The objective of this study was to quantify the prevalence of misdiagnosed moderate to severe cellulitis through an evaluation by an infectious diseases specialist, characterize the alternative diagnoses, and assess variables associated with misdiagnosis.

Methods

A prospective cross-sectional study of adults referred from emergency departments with presumed moderate to severe cellulitis to an outpatient parenteral antibiotic clinic staffed by infectious diseases specialists.

Results

301 consecutive patients with presumed cellulitis were evaluated over a 6-month period. A concurring diagnosis of cellulitis was found in 170 patients (56.5%), for a misdiagnosis rate of 43.5% (131/301). Table 1 summarizes the alternative diagnoses. Infectious conditions other than cellulitis were the most common (63/301; 20.9%), with abscess being present in 23 (7.6%) of patients. Fifty-two of 301 (17.3%) of the diagnoses were noninfectious and 16/301 (5.3%) patients had a dual diagnosis where minor cellulitis was present, but secondary to another, predomintating condition. The presence of stasis dermatitis (OR 6.62, P = 0.013) and a history of physical trauma (OR 1.76, P = 0.046) were associated with a misdiagnosis. 31.9% (107/335) of antibiotic regimens prescribed by emergency physicians were inappropriate or sub-optimal compared with 7.9% (22/280) of those ordered by infectious disease doctors.

Conclusion

Moderate to severe cellulitis was incorrectly diagnosed in nearly half of the patients referred for intravenous antibiotics and resulted in a high rate of unstewardly antimicrobial use. Infectious diseases physicians at an outpatient antibiotic clinic improved the diagnostic accuracy and management of this complicated condition.

Disclosures

All authors: No reported disclosures.

The impact of drug reimbursement policy on rates of testosterone replacement therapy among older men

Background

Despite a lack of data describing the long-term efficacy and safety of testosterone replacement therapy (TRT), prescribing of testosterone to older men has increased with the availability of topical formulations. The magnitude of this increase and the impact of formulary restrictions on testosterone prescribing are poorly characterized.

Methods

We conducted a time series analysis using the linked health administrative records of men aged 66 years or older in Ontario, Canada between January 1, 1997 and March 31, 2012. We used interventional autoregressive integrated moving average models to examine the impact of a restrictive drug reimbursement policy on testosterone prescribing and examined the demographic profile of men initiating testosterone in the final 2 years of the study period.

Results

A total of 28,477 men were dispensed testosterone over the study period. Overall testosterone prescribing declined 27.9% in the 6 months following the implementation of the restriction policy (9.5 to 6.9 men per 1000 eligible; p<0.01). However, the overall decrease was temporary and testosterone use exceeded pre-policy levels by the end of the study period (11.0 men per 1000 eligible), largely driven by prescriptions for topical testosterone (4.8 men per 1000 eligible). Only 6.3% of men who initiated testosterone had a documented diagnosis of hypogonadism, the main criteria for TRT reimbursement according to the new policy.

Conclusion

Government-imposed restrictions did not influence long-term prescribing of testosterone to older men. By 2012, approximately 1 in every 90 men aged 66 or older was being treated with TRT, most with topical formulations.

[Preoperative autotransfusion and hemodilution and its value in reconstructive vascular surgery]

Autotransfusion and haemodilution are the most safe and well known methods of blood protection in patients planned for vascular operations. During reconstructive vascular surgery autotransfusion with hypovolemic or normovolemic haemodilution were used. In the I group of patients hypovolemic haemodilution was done. In the II group of patients vascular bed was filed up with Ringer solution or with 6% solution of hydroxyethyl starch. The type of haemodilution and its influence on haemodynamics were estimated. Investigations were done by echocardiograph: ATL ULTRAMARK 8. It was concluded that the most effective are autotransfusion and normovolemic haemodilution with filing up vascular bed with Ringer solution.