Protection Conferred by COVID-19 Vaccination, Prior SARS-CoV-2 Infection, or Hybrid Immunity Against Omicron-Associated Severe Outcomes Among Community-Dwelling Adults

INTRODUCTION

We assessed protection from coronavirus disease 2019 (COVID-19) vaccines and/or prior severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection against Omicron-associated severe outcomes during successive sublineage-predominant periods.

METHODS

We used a test-negative design to estimate protection by vaccines and/or prior infection against hospitalization/death among community-dwelling, polymerase chain reaction (PCR)-tested adults aged ≥50 years in Ontario, Canada, between 2 January 2022 and 30 June 2023. Multivariable logistic regression was used to estimate the relative change in the odds of hospitalization/death with each vaccine dose (2-5) and/or prior PCR-confirmed SARS-CoV-2 infection (compared with unvaccinated, uninfected subjects) up to 15 months since the last vaccination or infection.

RESULTS

We included 18 526 cases with Omicron-associated severe outcomes and 90 778 test-negative controls. Vaccine protection was high during BA.1/BA.2 predominance but was generally <50% during periods of BA.4/BA.5 and BQ/XBB predominance without boosters. A third/fourth dose transiently increased protection during BA.4/BA.5 predominance (third-dose, 6-month: 68%, 95% confidence interval [CI] 63%-72%; fourth-dose, 6-month: 80%, 95% CI 77%-83%) but was lower and waned quickly during BQ/XBB predominance (third-dose, 6-month: 59%, 95% CI 48%-67%; 12-month: 49%, 95% CI 41%-56%; fourth-dose, 6-month: 62%, 95% CI 56%-68%, 12-months: 51%, 95% CI 41%-56%). Hybrid immunity conferred nearly 90% protection throughout BA.1/BA.2 and BA.4/BA.5 predominance but was reduced during BQ/XBB predominance (third-dose, 6-month: 60%, 95% CI 36%-75%; fourth-dose, 6-month: 63%, 95% CI 42%-76%). Protection was restored with a fifth dose (bivalent; 6-month: 91%, 95% CI 79%-96%). Prior infection alone did not confer lasting protection.

CONCLUSIONS

Protection from COVID-19 vaccines and/or prior SARS-CoV-2 infections against severe outcomes is reduced when immune-evasive variants/subvariants emerge and may also wane over time. Our findings support a variant-adapted booster vaccination strategy with periodic review.

Effectiveness of mRNA COVID-19 Monovalent and Bivalent Vaccine Booster Doses Against Omicron Severe Outcomes Among Adults Aged ≥50 Years in Ontario, Canada: A Canadian Immunization Research Network Study

We estimated the effectiveness of booster doses of monovalent and bivalent mRNA COVID-19 vaccines against Omicron-associated severe outcomes among adults aged ≥50 years in Ontario, Canada. Monovalent and bivalent mRNA COVID-19 booster doses provided similar strong initial protection against severe outcomes. Uncertainty remains around waning of protection from these vaccines.

Community and Health Care Provider Preferences for Bacterial Sexually Transmitted Infection Testing Interventions for Gay, Bisexual, and Other Men Who Have Sex With Men: e-Delphi Study

BACKGROUND

Canadian clinical guidelines recommend at least annual and up to quarterly bacterial sexually transmitted infection (STI) testing among sexually active gay, bisexual, and other men who have sex with men (GBM). However, testing rates are suboptimal. Innovative solutions are needed to close the gap because there is currently limited knowledge on how best to approach this issue.

OBJECTIVE

Our aim was to build consensus regarding interventions with the greatest potential for improving local STI testing services for GBM communities in Toronto, Ontario, Canada, using a web-based e-Delphi process.

METHODS

The e-Delphi method involves using a panel format to conduct successive rounds of prioritization, with feedback between rounds, to determine priorities among groups. We recruited experts separately from the community (GBM who sought or underwent STI testing in the preceding 18 months; conducted between October 2019 and November 2019) and health care providers (those who offered STI testing to GBM in the past 12 months; conducted between February 2020 and May 2020). The experts prioritized 6 to 8 potential interventions on a 7-point Likert scale ranging from definitely not a priority to definitely a priority over 3 survey rounds and ranked their top 3 interventions. Consensus was defined as ≥60% within a ±1 response point. Summaries of responses were provided in successive rounds. We reported the percentage of a priority (encompassing somewhat a priority, a priority, and definitely a priority responses) at the end of the final round of the survey.

RESULTS

Of the community experts (CEs), 84% (43/51) completed all rounds; 19% (8/43) were living with HIV; 37% (16/43) were HIV negative and on pre-exposure prophylaxis; and 42% (18/43) were HIV negative and not on pre-exposure prophylaxis. We reached consensus on 6 interventions: client reminders (41/43, 95%), express testing (38/43, 88%), routine testing (36/43, 84%), an online booking app (36/43, 84%), online-based testing (33/43, 77%), and nurse-led testing (31/43, 72%). The CEs favored convenient interventions that also maintain a relationship with their provider. Of the provider experts (PEs), 77% (37/48) completed all rounds; 59% (22/37) were physicians. Consensus was reached on the same 6 interventions (range 25/37, 68%, to 39/39, 100%) but not for provider alerts (7/37, 19%) and provider audit and feedback (6/37, 16%). Express testing, online-based testing, and nurse-led testing were prioritized by >95% (>37/39) of the PEs by the end of round 2 because of streamlined processes and decreased need to see a provider.

CONCLUSIONS

Both panels were enthusiastic about innovations that make STI testing more efficient, with express testing rating highly in both the prioritizations and top 3 rankings. However, CEs preferred convenient interventions that involved their provider, whereas PEs favored interventions that prioritized patient independence and reduced patient-provider time.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.2196/13801.

Vaccine Effectiveness Against 12-Month Incident and Persistent Anal Human Papillomavirus Infection Among Gay, Bisexual, and Other Men Who Have Sex With Men

BACKGROUND

Real-world evidence of human papillomavirus (HPV) vaccine effectiveness (VE) against longitudinal outcomes is lacking among gay, bisexual, and other men who have sex with men (GBM). We compared 12-month incidence and persistence of anal HPV infection between vaccinated and unvaccinated GBM.

METHODS

We recruited GBM aged 16-30 years in Montreal, Toronto, and Vancouver, Canada, from 2017 to 2019. Participants were followed over a median of 12 months (interquartile range, 12-13 months). Participants self-reported HPV vaccination and self-collected anal specimens for HPV DNA testing. We calculated prevalence ratios (PR) for 12-month cumulative incidence and persistence with ≥1 quadrivalent vaccine type (HPV 6/11/16/18) between vaccinated (≥1 dose at baseline) and unvaccinated participants using a propensity score-weighted, modified Poisson regression.

RESULTS

Among 248 participants, 109 (44.0%) were vaccinated at baseline, of whom 62.6% received 3 doses. PRs for HPV 6/11/16/18 were 0.56 (95% confidence interval [CI], .24-1.31) for cumulative incidence and 0.53 (95% CI, .25-1.14) for persistence. PRs were 0.23 (95% CI, .05-1.03) and 0.08 (95% CI, .01-.59) for incidence and persistence, respectively, among participants who received their first dose at age ≤23 years and 0.15 (95% CI, .03-.68) and 0.12 (95% CI, .03-.54) among participants who were sexually active for ≤5 years before vaccination.

CONCLUSIONS

Findings support national recommendations for HPV vaccination at younger ages or soon after sexual debut.

Self-reported Human Papillomavirus Vaccination and Vaccine Effectiveness Among Men Who Have Sex with Men: A Quantitative Bias Analysis

BACKGROUND

Self-report of human papillomavirus (HPV) vaccination has ~80-90% sensitivity and ~75-85% specificity. We measured the effect of nondifferential exposure misclassification associated with self-reported vaccination on vaccine effectiveness (VE) estimates.

METHODS

Between 2017-2019, we recruited sexually active gay, bisexual, and other men who have sex with men aged 16-30 years in Canada. VE was derived as 1-prevalence ratio × 100% for prevalent anal HPV infection comparing vaccinated (≥1 dose) to unvaccinated men using a multivariable modified Poisson regression. We conducted a multidimensional and probabilistic quantitative bias analysis to correct VE estimates.

RESULTS

Bias-corrected VE estimates were relatively stable across sensitivity values but differed from the uncorrected estimate at lower values of specificity. The median adjusted VE was 27% (2.5-97.5th simulation interval = -5-49%) in the uncorrected analysis, increasing to 39% (2.5-97.5th simulation interval = 2-65%) in the bias-corrected analysis.

CONCLUSION

A large proportion of participants erroneously reporting HPV vaccination would be required to meaningfully change VE estimates.

Influence of previous experience with and beliefs regarding anal cancer screening on willingness to be screened among men living with HIV

BACKGROUND

Implementation of anal cancer screening requires the procedure to be acceptable to the target population. Our objective was to assess the beliefs of men living with HIV regarding anal cancer screening and identify factors associated with their willingness to participate in screening.

METHODS

We developed a cross-sectional questionnaire using the Theory of Planned Behavior to examine beliefs regarding prevention of human papillomavirus (HPV)-related diseases, administered to men living with HIV in 2016-2017 in a multi-site HIV clinical cohort. Correspondence analysis was used to examine the interrelationships between men's beliefs and willingness to undergo anal cancer screening. We used multivariable proportional odds models to identify factors associated with increasing willingness. Results were reported as adjusted odds ratios (aOR) with 95% confidence intervals (CI).

RESULTS

Among 1677 male participants, the vast majority (90%) would be willing to undergo screening by "anal Pap test"; willingness clustered with positive beliefs (e.g. confident they can get screened; disagree that they will feel pain) in the correspondence analysis. Higher self-perceived risk for anal cancer and positive beliefs regarding screening were associated with higher willingness to be screened. Gay, bisexual and other men who have sex with men had higher willingness (aOR = 1.62; 95% CI: 1.15, 2.29) than heterosexual men. Racialized men reported lower willingness (aOR = 0.68; 95% CI: 0.54, 0.89) than white men.

CONCLUSIONS

Men generally had positive beliefs and were willing to undergo screening, though there were differences by sexual orientation and racial identity. Tailored community-led initiatives could focus on men's understanding of their risk and expectations of anal cancer screening to facilitate participation.

Effectiveness and Duration of Protection of a Fourth Dose of COVID-19 mRNA Vaccine among Long-Term Care Residents in Ontario, Canada

We estimated the effectiveness of a fourth dose of mRNA COVID-19 vaccine against Omicron infections and severe outcomes over time among long-term care residents in Ontario, Canada. Fourth doses provide additional protection against Omicron-related outcomes, but the protection wanes over time, with more waning seen against infection than severe outcomes.

Low human papillomavirus vaccine uptake among women engaged in HIV care in Ontario, Canada

Women living with HIV are at higher risk for human papillomavirus (HPV)-related dysplasia and cancers and thus are prioritized for HPV vaccination. We measured HPV vaccine uptake among women engaged in HIV care in Ontario, Canada, and identified socio-demographic, behavioural, and clinical characteristics associated with HPV vaccination. During annual interviews from 2017 to 2020, women participating in a multi-site, clinical HIV cohort responded to a cross-sectional survey on HPV vaccine knowledge and receipt. We used logistic regression to derive age-adjusted odds ratios and 95% confidence intervals (CI) for factors associated with self-reported vaccine initiation (≥1 dose) or series completion (3 doses). Among 591 women (median age = 48 years; interquartile range = 40-56 years), 13.2% (95%CI = 10.5-15.9%) had received ≥1 dose. Of those vaccinated, 64.6% had received 3 doses. Vaccine initiation (≥1 dose) was significantly higher among women aged 20-29 years at 31.0% but fell to 13.9% in those aged 30-49 years and < 10% in those aged ≥50 years. After age adjustment, vaccine initiation was significantly associated with being employed (vs. unemployed but seeking work), income $40,000-$59,999 (vs. <$20,000), being married/common-law (vs. single), living with children, immigrating to Canada >5 years ago (vs. immigrating ≤5 years ago), never smoking (vs. currently smoking), and being in HIV care longer (per 10 years). Similar factors were identified for series completion (3 doses). HPV vaccine uptake remains low among women living with HIV in our cohort despite regular engagement in care. Recommendations for improving uptake include education of healthcare providers, targeted community outreach, and public funding of HPV vaccination.

Effectiveness of a fourth dose of covid-19 mRNA vaccine against the omicron variant among long term care residents in Ontario, Canada: test negative design study

OBJECTIVES

To estimate the marginal effectiveness of a fourth versus third dose and the vaccine effectiveness of mRNA covid-19 vaccines BNT162b2 and mRNA-1273 against any infection, symptomatic infection, and severe outcomes (hospital admission or death) related to the omicron variant.

DESIGN

Test negative design.

SETTING

Long term care facilities in Ontario, Canada, 30 December 2021 to 27 April 2022.

PARTICIPANTS

After exclusions, 61 344 residents aged 60 years or older across 626 long term care facilities in Ontario, Canada who were tested for SARS-CoV-2 were included.

MAIN OUTCOME MEASURES

Laboratory confirmed omicron SARS-CoV-2 infection (any and symptomatic) by reverse transcription polymerase chain reaction (RT-PCR), and hospital admission or death. Multivariable logistic regression was used to estimate marginal effectiveness (four versus three doses) and vaccine effectiveness (two, three, or four doses versus no doses) while adjusting for personal characteristics, comorbidities, week of test, and previous positive SARS-CoV-2 test result more than 90 days previously.

RESULTS

13 654 residents who tested positive for omicron SARS-CoV-2 infection and 205 862 test negative controls were included. The marginal effectiveness of a fourth dose (95% of vaccine recipients received mRNA-1273 as the fourth dose) seven days or more after vaccination versus a third dose received 84 or more days previously was 19% (95% confidence interval 12% to 26%) against infection, 31% (20% to 41%) against symptomatic infection, and 40% (24% to 52%) against severe outcomes. Vaccine effectiveness in vaccine recipients (compared with unvaccinated) increased with each additional dose, and for a fourth dose was 49% (95% confidence interval 43% to 54%) against infection, 69% (61% to 76%) against symptomatic infection, and 86% (81% to 90%) against severe outcomes.

CONCLUSIONS

The findings suggest that compared with a third dose of mRNA covid-19 vaccine, a fourth dose improved protection against infection, symptomatic infection, and severe outcomes among long term care residents during an omicron dominant period. A fourth vaccine dose was associated with strong protection against severe outcomes in vaccinated residents compared with unvaccinated residents, although the duration of protection remains unknown.

Human papillomavirus (HPV) vaccination across a cascade of knowledge, willingness, and uptake among gay, bisexual, and other men who have sex with men in Canada's three largest cities

BACKGROUND

Some Canadian jurisdictions offer publicly funded HPV vaccine to gay, bisexual, and other men who have sex with men (GBM) aged ≤26 years. We characterized factors associated with being in different stages of HPV vaccination.

METHODS

Engage is a sexual health study of GBM in the three largest Canadian cities recruited via respondent driven sampling (RDS). We categorized participants as: (1) unaware of HPV vaccine, (2) undecided/unwilling to get vaccinated, (3) willing to get vaccinated, (4) vaccinated with one or more doses. Our RDS-II weighted analyses used multinomial logistic regression to identify factors associated with being in earlier stages of the cascade compared to Stage 4.

RESULTS

Across the cities, 26-40%, 7-14%, 33-39%, and 13-28% were in Stages 1 to 4, respectively. Compared to Stage 4, being in earlier stages of the cascade was associated with bisexual-identification (Stage 1: adjusted odds ratio[aOR] = 2.84, 95% confidence interval[CI] = 1.06-7.62; Stage 2: aOR = 3.09, 95%CI = 1.19-8.05), having immigrated to Canada (Stage 1: aOR = 1.79, 95%CI 1.07-2.99), preference to keep same-sex romantic relationships private (Stage 1: aOR = 1.25, 95% CI = 1.05-1.48; Stage 2: aOR = 1.24, 95%CI = 1.05-1.46), not receiving sexual health information (Stage 1: aOR = 0.31, 95% CI = 0.13-0.71; Stage 2: aOR = 0.27, 95%CI = 0.12-0.64), not accessing a health-care provider (Stage 2: aOR = 0.36, 95%CI = 0.15-0.83), and no past hepatitis A/B vaccination (Stage 1: aOR = 0.16, 95% CI = 0.09-0.30; Stage 2: aOR = 0.18, 95%CI = 0.09-0.35; Stage 3: aOR = 0.38, 95%CI = 0.21-0.61).

DISCUSSION

Interventions are needed to reduce social and financial barriers, increase sexual health knowledge, and improve GBM-competent health-care access to increase vaccine uptake among GBM.

Hepatitis C virus testing in a clinical HIV cohort in Ontario, Canada, 2000 to 2015

BACKGROUND

HIV-positive individuals may acquire HCV via injection drug use (IDU) and condomless anal sex. HIV care provides opportunities for HCV testing and cure with direct-acting antiviral agents (DAAs).

METHODS

We analyzed data from the Ontario HIV Treatment Network Cohort Study. Among those not HCV-positive or diagnosed previously (n = 4586), we used Cox regression to test the rates of ever HCV testing (serological or RNA) in HIV care by DAA era (pre-DAA: 2000-2010; after DAA: 2011-2015) and compared the proportion diagnosed with HCV. We identified correlates of annual proportions of serological testing using Poisson generalized estimating equations.

RESULTS

After DAA vs pre-DAA, the hazard rate ratio (95% CI) of ever HCV testing was 1.70 (1.59, 1.81). The proportion (95% CI) tested annually increased from 9.2% (8.0%, 10.7%) in 2000 to 39.1% (37.1%, 41.1%) in 2015 (P < 0.0001). The proportion diagnosed with HCV declined by 74% pre-DAA to 11% after DAAs. Annual testing increased per calendar year (16% steeper slope after DAA vs pre-DAA) and was more common among men who have sex with men; those more educated (post-secondary vs ≤ high school); and those positive for syphilis or reporting any IDU. Annual testing decreased per decade of age and time since HIV diagnosis.

DISCUSSION

Annual HCV testing increased over time with higher testing among those reporting sexual or IDU risk factors, but fell short of clinical guidelines. Targeted interventions to boost testing may be needed to close these gaps and reach WHO 2030 HCV elimination targets.

Patient perspectives on the implementation of routinised syphilis screening with HIV viral load testing: Qualitative process evaluation of the Enhanced Syphilis Screening Among HIV-positive Men trial

BACKGROUND

Syphilis infections have been on the rise, affecting men living with HIV in urban centres disproportionately. Since individuals in HIV care undergo routine blood testing, HIV clinics provide practical opportunities to conduct regular and frequent syphilis testing. Following the implementation of a routine syphilis testing intervention in HIV outpatient clinics, we conducted a qualitative process evaluation of patient experiences to measure patient acceptability, barriers to implementation, and facilitators of successful uptake.

METHODS

Upon completion of the trial, which took place at four HIV outpatient clinics in Toronto and Ottawa, Canada, we recruited male patients attending these clinics from November 2017 to April 2018. Interviews were conducted on-site and were audio-recorded and transcribed verbatim. All participants provided written informed consent. Interview data were analyzed using grounded theory, assessing qualitative modulators of effective uptake of routinised syphilis testing.

RESULTS

A total of 21 male patients were interviewed. Overall, interviewees found the clinical intervention acceptable, endorsing the practice of routinising syphilis testing alongside regular viral load bloodwork. Some men preferred, based on their self-assessment of syphilis risk, to opt out of testing; we considered this as a potential barrier to uptake of population-wide routinised syphilis testing. Interviewees also identified multiple facilitators of successful uptake, including the de-stigmatising of STI testing as a consequence of the universal nature of routinised testing. Participants recommended a routinised syphilis screening intervention to give patients peace of mind surrounding their sexual health. Participants identified HIV care clinics as comfortable and efficient locations to offer testing.

CONCLUSIONS

Overall, most men were in support of implementing routinised syphilis testing as part of standard HIV care. From the patient perspective, HIV care clinics are convenient places to be tested for syphilis, and the routine approach was viewed to have a de-stigmatisng effect on syphilis testing.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02019043; registered December 23, 2013.

Routinised Syphilis Screening among Men Living with HIV: A stepped wedge cluster randomised controlled trial

BACKGROUND

Frequent syphilis screening may increase early detection and decrease transmission. We implemented an opt-out clinic-based intervention pairing syphilis tests with routine HIV viral load testing. The primary objective was to determine the degree to which this intervention increased the detection of early syphilis.

METHODS

The Enhanced Syphilis Screening among HIV-positive Men (ESSAHM) Trial was a stepped wedge cluster-randomised controlled trial involving four urban HIV clinics in Ontario, Canada, from 2015 to 2017. Population: HIV-positive adult males. Intervention (I): standing orders for syphilis serological testing with viral loads. Control (C): usual practice. Outcome: early syphilis diagnosis. We obtained test results via linkage with the centralized provincial laboratory and defined cases using a standardized clinical worksheet and medical chart review. We employed a generalized linear mixed model with a logit link to estimate odds ratios (OR) and 95% confidence intervals (CI) of the intervention.

FINDINGS

3,895 men were followed over 7,471 person-years (PY). The mean number of syphilis tests increased from 0.53 to 2.02 tests per person per year. There were 217 new diagnoses of syphilis (C: 81; I: 136), for which 147 (68%) were cases of early syphilis (C:61 (75%); I:86 (63%)). The annualized proportion with newly-detected early syphilis increased from 0.009 to 0.032 with implementation of the intervention; the corresponding time-adjusted OR was 1.25 (CI 0.71, 2.20).

INTERPRETATION

The implementation of standing orders for syphilis testing with HIV viral loads was feasible and increased testing yet produced less-than-expected increases in case detection compared to past uncontrolled pre-post trials.

Human papillomavirus (HPV) vaccine uptake among a community-recruited sample of gay, bisexual, and other men who have sex with men in the three largest cities in Canada from 2017 to 2019

INTRODUCTION

In 2015/2016, Canada's largest provinces implemented publicly-funded human papillomavirus (HPV) vaccination programs for gay, bisexual, and other men who have sex with men (GBM) ≤ 26 years old. We sought to describe HPV vaccine uptake among GBM and determine barriers and facilitators to vaccine initiation with a focus on healthcare access and utilization.

METHODS

Engage is a cohort study among GBM aged 16 + years in three Canadian cities recruited from 2017 to 2019 via respondent driven sampling (RDS). Men completed a comprehensive questionnaire at baseline. By publicly-funded vaccine eligibility (≤26 years old = eligible for vaccination, ≥27 years old = ineligible), we described HPV vaccine uptake (initiation = 1 + dose, completion = 3 doses) and explored factors associated with vaccine initiation using Poisson regression. All analyses were weighted with the RDS-II Volz-Heckathorn estimator.

RESULTS

Across the three cities, 26-35% and 14-21% of men ≤ 26 years and 7-26% and 2-9% of men ≥ 27 years initiated and completed HPV vaccination, respectively. Vaccine initiation was significantly associated with STI/HIV testing or visiting a HIV care specialist in the past six months (≤26: prevalence ratio[PR] = 2.15, 95% confidence interval[CI] 1.06-4.36; ≥27: PR = 2.73, 95%CI 1.14-6.51) and past hepatitis A or B vaccination (≤26: PR = 2.88, 95%CI 1.64-5.05; ≥27: PR = 2.03, 95%CI 1.07-3.86). Among men ≥ 27 years old, vaccine initiation was also positively associated with accessing PrEP, living in Vancouver or Toronto, but negatively associated with identifying as Latin American and increasing age. Vaccine initiation was twice as likely among men ≥ 27 years with private insurance versus no insurance.

CONCLUSIONS

Sixty-five to 74% of men eligible for publicly-funded vaccine across the three cities remained unvaccinated against HPV by 2019. High vaccine cost may partly explain even lower uptake among men ≥ 27 years old. Men seeking sexual health care were more likely to initiate vaccination; bundling vaccination with these services may help improve HPV vaccine uptake.

Survey of Health Care Providers' Practices and Opinions Regarding Bacterial Sexually Transmitted Infection Testing Among Gay, Bisexual, and Other Men Who Have Sex With Men

BACKGROUND

Rates of bacterial sexually transmitted infections (STIs) continue to rise among gay, bisexual, and other men who have sex with men (GBMSM) globally. Testing and treatment can prevent morbidity and transmission. However, testing rates remain suboptimal.

METHODS

In 2018, we conducted an online cross-sectional survey to explore STI testing ordering practices, 14 potential barriers for testing and 11 possible ways to improve testing from the perspective of health care providers in Toronto, Ontario. An estimated 172 providers were invited from primary care and sexual health clinic settings. Providers were eligible to complete the survey if they provided care for ≥1 GBMSM per week and were involved in the decision-making process in providing STI tests. We used descriptive statistics to summarize survey responses.

RESULTS

Ninety-five providers (55% response rate) participated, of whom 68% worked in primary care and 32% in sexual health settings. Most (66%) saw ≤10 GBMSM clients per week. In primary care (65%) and sexual health (40%) clinic settings, insufficient consultation time was the most common barrier to STI testing. In primary care, other common barriers included difficulty introducing testing during unrelated consultations (53%), forgetting (47%), and patients being sexually inactive (31%) or declining testing (27%). The following were most likely to improve testing: express/fast-track testing services (89%), provider alerts when patients are due for testing (87%), patient-collected specimens (84%), nurse-led STI testing (79%), and standing orders (79%).

CONCLUSIONS

Promising interventions to improve bacterial STI testing included initiatives that simplify and expedite testing and expand testing delivery to other health care professionals.

Low human papillomavirus (HPV) knowledge related to low risk perception among men living with HIV: Implications for HPV-associated disease prevention

Human papillomavirus (HPV)-associated anal cancer is orders of magnitude higher among men living with HIV than the general male population. Our objective was to examine factors associated with HPV awareness and self-perceived risk for HPV-associated anal cancer among men living with HIV, which may influence uptake of cancer prevention strategies. A cross-sectional questionnaire on HPV was administered from 2016 to 2017 to 1677 men in a multisite, HIV clinical cohort in Ontario, Canada. We used logistic regression and proportional odds models to identify factors associated with being familiar with HPV and increasing self-perceived risk for anal cancer, respectively. We used correspondence analysis to examine associations of specific HPV-related knowledge with self-perceived risk. Only 52% were familiar with HPV, and 72% felt they had no or low risk for anal cancer. Familiarity with HPV was more common among men who have sex with men than heterosexual men (58% vs. 21%). Older men were less likely to be familiar with HPV (adjusted odds ratio [aOR] per 10 years = 0.77; 95% confidence interval [CI]: 0.69, 0.85). Familiarity with HPV was associated with increasing self-perceived risk (aOR = 2.39; 95% CI: 1.87, 3.04). After accounting for differences in HPV awareness and sexual orientation, racialized men had lower self-perceived risk (aOR = 0.68; 95% CI: 0.52, 0.88). In the correspondence analysis, risk-focused HPV-related knowledge (e.g., knowing smoking increases risk) was associated with highest risk perception. Efforts are needed to improve HPV-related health literacy in this population. Our findings suggest specific HPV-related knowledge may differentially influence self-perceived risk for anal cancer.

0675 Nocturnal Oxygen Supplementation With Positive Airway Pressure Therapy For Obesity Hypoventilation Syndrome: Clinical Predictors And Liberation From Oxygen

Introduction

Obesity hypoventilation syndrome (OHS) is associated with a high morbidity and mortality. Many patients require nocturnal supplemental oxygen on top of positive airway pressure (PAP) therapy for hypoxemia independent of apneic events. We need to clinically identify patients likely to require nocturnal oxygen supplementation. Follow up is essential as with adequate control of sleep apnea, hypoxia improves and liberation from nocturnal oxygen supplementation may be achievable.

Methods

Researchers obtained a list of patients with coding diagnosis of OHS, seen at the Jefferson Sleep Center between November 2016 and September 2019. Patients with BMI of ≥ 30 and evidence of hypoventilation were included. Hypoventilation was defined as an elevated CO2 level of ≥ 45 mmHg on blood gas analysis, elevated serum bicarbonate level of ≥ 27 mmol/L or by evidence of nocturnal hypoventilation by AASM criteria on polysomnography. Patients with pulmonary and neuromuscular disorders were excluded

Results

Out of 189 patients reviewed, 36 met the inclusion and exclusion criteria. Nineteen patients (53%) required nocturnal oxygen supplementation. A higher serum bicarbonate level of 33 mmol/L against 30 mmol/L (p=0.0078) and a lower resting awake SaO2 of 89% versus 95% (p &lt;0.01) were observed in the oxygen supplementation group. In polysomnographic data, the oxygen supplementation group had lower SaO2 nadir of 67% versus 73% (p=0.026) and had a longer time with SaO2 &lt;88% at 238.2 minutes versus 65.5 minutes (p &lt;0.01). Nine out of the 19 patients (47%) underwent nocturnal oximetry on PAP and room air. Of these, 4 patients (44%) were liberated from oxygen.

Conclusion

Fifty three percent of patients with OHS required nocturnal oxygen supplementation on top of PAP therapy. Higher serum bicarbonate level and lower resting awake SaO2 are potential clinical predictors of nocturnal oxygen supplementation. After nocturnal oximetry on PAP, 44% were successfully liberated from supplemental oxygen.

Support

 

Brief Report: Syphilis Coinfection Is Not Associated With an Increased Risk of Virologic Failure Among HIV-Positive Men Who Have Sex With Men on Antiretroviral Therapy

BACKGROUND

Incidence of syphilis continues to increase among HIV-positive men who have sex with men (MSM) in Ontario. Our objective was to determine the effect of acute syphilis on virologic failure (VF) among virally suppressed HIV-positive MSM taking antiretroviral therapy (ART) and determine if the relationship is confounded by drug use.

SETTING

The OHTN Cohort Study is a voluntary cohort of people receiving HIV care in Ontario. Syphilis and viral load (VL) data were retrieved via linkage with the provincial laboratory.

METHODS

Analyses included 2632 MSM from 2008 to 2015, on ART, with ≥1 questionnaire and 2 consecutive VL of <50 copies per milliliter 6 months apart. VF was defined as (1) VL of ≥1000 copies per milliliter or (2) 2 consecutive VLs of ≥200 copies per milliliter ≥1 month apart. We modeled acute syphilis as a time-varying covariate on VF using Poisson regression. Time-varying drug use was assessed for confounding using an iterative process where potential confounders were removed and then reintroduced into the model. Our model allowed for repeat observations using generalized estimating equations.

RESULTS

VF incidence was 3.5 per 100 person-years [95% confidence interval (CI): 3.4 to 4.2]. The rate ratio for VF for acute syphilis was 1.5 (95% CI: 0.9 to 2.4) in the unadjusted model; 1.6 (95% CI: 1.0 to 2.4) in the model adjusted for age, education, region, and income; and 1.2 (95% CI: 0.7 to 1.9) in the final model with additional adjustment for drug use.

CONCLUSIONS

Acute syphilis was not associated with VF among virologically suppressed MSM on ART. Consequently, ART may still reduce HIV transmission risk to sexual partners.

Economic barriers, evidentiary gaps, and ethical conundrums: a qualitative study of physicians' challenges recommending HPV vaccination to older gay, bisexual, and other men who have sex with men

BACKGROUND

The human papillomavirus (HPV) is the most common sexually transmitted infection (STI) worldwide. Gay, bisexual, and other men who have sex with men (GBM), and GBM living with HIV in particular, are disproportionately impacted by HPV-associated cancers. The HPV vaccine, given early enough in life, may markedly reduce the likelihood of such cancers. In Canada, most provincial insurance programs only cover HPV vaccination for GBM up to the age of 26. Our objective was to understand physicians' everyday experiences and challenges in recommending HPV vaccination to older GBM patients.

METHODS

As part of the HPV Screening and Vaccine Evaluation (HPV-SAVE) Study, we conducted semi-structured interviews with 25 HIV-positive GBM patients who had received anal cancer screening and 15 service providers, including 13 physicians, who had arranged for anal cancer screening in the Canadian provinces of Ontario and British Columbia. In this analysis, we draw upon the 13 physician interviews, which were coded following Grounded Theory.

RESULTS

Physicians strongly supported the HPV vaccine for all GBM and considered it to be important for the management of HIV-related care. However, the overall support for HPV vaccination among physicians did not translate into consistent recommendation practices. There were two overarching factors that limited the strength/frequency of physicians' vaccine recommendation practices. First, cost/insurance coverage for some older patients impacted if and how the HPV vaccine was discussed. Second, physicians had diverse perspectives on both the prevention and therapeutic benefits of vaccinating older GBM and the reality that national guidelines are incongruent with publicly funded vaccine programs for vaccinating patients over 26 years old. These two interrelated factors have co-produced an apparent economic-evidentiary conundrum for many physicians regarding how and for whom to offer HPV vaccination.

CONCLUSION

Economic barriers coupled with evidentiary and guideline gaps have created clinical practice challenges for physicians and has resulted in different messages being communicated to some older GBM patients about how important HPV vaccination is for their health.

Community-Directed Bacterial Sexually Transmitted Infection Testing Interventions Among Men Who Have Sex With Men: Protocol for an E-Delphi Study in Toronto, Canada

Background

HIV-positive and HIV-negative (gay, bisexual, and other) men who have sex with men (MSM) have experienced a dramatic increase in bacterial sexually transmitted infections (STIs)—syphilis, gonorrhea, and chlamydia. STI testing and treatment mitigate adverse health outcomes and substantially reduce transmission; yet, testing rates remain below recommended levels. Innovation is needed to produce the required increases in testing levels, frequency, and the use of appropriate testing technologies in ways that are engaging, nonstigmatizing, and acceptable to men.

Objective

The aim of this study is to build consensus with regard to interventions with the greatest potential for improving local STI testing services for MSM communities in Toronto, Canada.

Methods

Following a literature review of evidence regarding the effectiveness of novel testing interventions, and focus groups, and surveys to describe local barriers and facilitators of testing among MSM, we will conduct a Web-based, modified Delphi study (e-Delphi). We will form expert panels of community members and STI test providers. Panelists will rate potential interventions in terms of their priority, using a 7-point Likert scale from definitely not a priority to definitely a priority. They will also rank their preferences by selecting their top 3 preferred interventions. Surveys will be distributed in 3 rounds, with feedback on the distribution of responses from preceding rounds provided in rounds 2 and 3. We will define consensus as having ≥60% (18/30) members indicate a preference within 2 adjacent response points. Qualitative data on disagreements will be obtained using open-ended text responses to explain for ratings and rankings that are different from the majority.

Results

On the basis of a literature review and identification of barriers and facilitators to STI testing among community members and test providers in Toronto, we have selected 8 potential interventions for inclusion in the e-Delphi panel surveys. These include 4 interventions that streamline STI testing for asymptomatic individuals, 2 interventions that are targeted at clients and 2 interventions that are targeted at providers.

Conclusions

Findings will provide community direction for informed decision making regarding the implementation of STI testing interventions in this setting. They will characterize the intervention climate for innovation to STI testing services, including perceived needs for changes to test delivery, relative priorities for change, and readiness for implementation. These methods may be transferable to other urban jurisdictions experiencing similar epidemics and for other contexts where stakeholder input is needed to manage sensitive areas of concern.

International Registered Report Identifier (IRRID)

PRR1-10.2196/13801

Sex-associated differences in mitochondrial function in human peripheral blood mononuclear cells (PBMCs) and brain

BACKGROUND

Alzheimer's disease (AD) is the most common form of dementia, and it affects more women than men. Mitochondrial dysfunction (MD) plays a key role in AD, and it is detectable at an early stage of the degenerative process in peripheral tissues, such as peripheral mononuclear blood cells (PBMCs). However, whether these changes are also reflected in cerebral energy metabolism and whether sex-specific differences in mitochondrial function occur are not clear. Therefore, we estimated the correlation between mitochondrial function in PBMCs and brain energy metabolites and examined sex-specific differences in healthy participants to elucidate these issues.

METHODS

The current pilot study included 9 male and 15 female healthy adults (mean age 30.8 ± 7.1 years). Respiration and activity of mitochondrial respiratory complexes were measured using a Clarke-electrode (Oxygraph-2k system), and adenosine triphosphate (ATP) levels were determined using a bioluminescence-based assay in isolated PBMCs. Citrate synthase activity as a mitochondrial marker was measured using a photometric assay. Concentrations of brain energy metabolites were quantified in the same individuals using 1H-magnetic resonance spectroscopy (MRS).

RESULTS

We detected sex-associated differences in mitochondrial function. Mitochondrial complexes I, I+II, and IV and uncoupled respiration and electron transport system (ETS) capacity in PBMCs isolated from blood samples of females were significantly (p < 0.05; p < 0.01) higher compared to males. ATP levels in the PBMCs of female participants were approximately 10% higher compared to males. Citrate synthase (CS) activity, a marker of mitochondrial content, was significantly (p < 0.05) higher in females compared to males. Sex-associated differences were also found for brain metabolites. The N-acetylaspartate (NAA) concentration was significantly higher in female participants compared to males in targeted regions. This difference was observed in white matter (WM) and an area with a high percentage (> 50%) of gray matter (GM) (p < 0.05; p < 0.01). The effect sizes indicated a strong influence of sex on these parameters. Sex-associated differences were found in PBMCs and brain, but the determined parameters were not significantly correlated.

CONCLUSIONS

Our study revealed sex-associated differences in mitochondrial function in healthy participants. The underlying mechanisms must be elucidated in more detail, but our study suggests that mitochondrial function in PBMCs is a feasible surrogate marker to detect differences in mitochondrial function and energy metabolism in humans and it underscores the necessity of sex-specific approaches in therapies that target mitochondrial dysfunction.

Sociodemographic and Health Profile of Heterosexual Men Living With HIV in Ontario, Canada

In Ontario, Canada, the number of heterosexual men living with HIV has increased over time, yet they remain an understudied population. The study objective was to describe the sociodemographic and clinical characteristics of this population, using data from a multisite clinical cohort of patients receiving HIV care. Sociodemographic and clinical characteristics of men interviewed between 2010 and 2012 were compared according to their self-identified sexual orientation, followed by multivariable linear and logistic regression to assess the association of sexual orientation with CD4 cell count, viral load, hepatitis C co-infection, self-rated health, and mental health concerns after adjustment for covariates. A total of 552 men identified as heterosexual, 2,023 as gay, and 171 as bisexual. Compared to gay and bisexual men, heterosexual men were more likely to have been born outside of Canada (34.8%); more likely to report African, Caribbean, or Black ethnicity (26.4%) or Indigenous ethnicity (13.6%); and more likely to have low socioeconomic status (59.5% earning less than $20,000 per year), and/or a history of injection drug use (31.7%). Relative to gay men, heterosexual men had 5.19 times the odds of co-infection with hepatitis C virus regardless of injection drug use history (95% confidence interval = 3.87-6.96), and 40% lower odds of rating their health as excellent or good (95% confidence interval = 0.50-0.84). HIV-positive heterosexual men in Ontario constituted a socially marginalized group characterized by a high prevalence of injection drug use history and hepatitis C co-infection.

Serosorting and recreational drug use are risk factors for diagnosis of genital infection with chlamydia and gonorrhoea among HIV-positive men who have sex with men: results from a clinical cohort in Ontario, Canada

OBJECTIVES

Rates of chlamydia and gonorrhoea have been rising in urban centres in Canada, particularly among HIV-positive men who have sex with men (MSM). Our objective was to identify behavioural risk factors for diagnosis with chlamydia and gonorrhoea in this population, with a focus on the HIV status of sexual partners.

METHODS

The OHTN Cohort Study follows people in HIV care across Ontario. We restricted the analysis to 1997 MSM who completed questionnaires in 2010-2013 at one of seven clinics that submit all chlamydia and gonorrhoea tests to the provincial public health laboratory; we obtained test results via record linkage. We estimated cumulative incidences using Kaplan-Meier methods and identified risk factors for diagnosis of a composite outcome (chlamydia or gonorrhoea infection) using Cox regression.

RESULTS

At follow-up, there were 74 new chlamydia/gonorrhoea diagnoses with a 12-month cumulative incidence of 1.7% (95% CI 1.1% to 2.2%). Risk factors for chlamydia/gonorrhoea diagnosis were: 5+ HIV-positive partners (HR=3.3, 95% CI 1.4 to 7.8; reference=none) and recreational drug use (HR=2.2, 95% CI 1.2 to 3.9).

CONCLUSIONS

Heightened risks with recreational drug use and multiple HIV-positive partners suggest that chlamydia/gonorrhoea may have achieved high prevalence in certain sexual networks among HIV-positive MSM. Interventions to promote safer sex and timely testing among MSM are needed.

Enhanced syphilis screening among HIV-positive men (ESSAHM): a study protocol for a clinic-randomized trial with stepped wedge design

BACKGROUND

The current syphilis epidemic among urban men who have sex with men (MSM) has serious implications for those co-infected with human immunodeficiency virus (HIV). Routine and frequent syphilis screening has the potential to ensure early detection and treatment, minimize disease burden, and help control the ongoing spread of syphilis and HIV. We aim to enhance syphilis screening among HIV-positive men by conducting a clinic-based intervention that incorporates opt-out syphilis testing into routine HIV laboratory evaluation for this population. Trial objectives are to determine the degree to which the intervention (1) increases the detection rate of untreated syphilis, (2) increases screening coverage, (3) increases screening frequency, and (4) reaches men at highest risk according to sexual behaviors.

METHODS/DESIGN

The trial is a pragmatic, stepped wedge cluster-randomized controlled trial that introduces the intervention stepwise across four urban HIV clinics in Ontario, Canada. The intervention includes standing orders for syphilis serological testing whenever a male in HIV care undergoes HIV viral load testing, which typically occurs every 3-6 months. The control condition is the maintenance of current, provider-initiated syphilis testing practice. Approximately 3100 HIV-positive men will be followed over 30 months. Test results will be obtained from the centralized provincial laboratory in Ontario and will be supplemented by a standardized clinical worksheet and medical chart review at the clinics. Detailed clinical, psychosocial, and behavioral data is available for a subset of men receiving HIV care who are also participants of the province-wide Ontario HIV Treatment Network Cohort Study. Process evaluation plans include audit and feedback of compliance of the participating centers to identify potential barriers to the introduction of this type of practice into routine care. Health economic components include evaluation of the impact and cost-effectiveness of the intervention.

DISCUSSION

This trial will be the first of its kind in Canada and will provide evidence regarding the feasibility, clinical effectiveness, and cost-effectiveness of a clinic-based intervention to improve syphilis screening among HIV-positive men. Involvement of knowledge users in all stages of trial design, conduct, and analysis will facilitate scale-up should the intervention be effective.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02019043.

High incidence of diagnosis with syphilis co-infection among men who have sex with men in an HIV cohort in Ontario, Canada

BACKGROUND

The re-emergence of syphilis among HIV-positive gay and other men who have sex with men (MSM) requires vigilance. We estimated incidence of and risk factors for first and subsequent syphilis diagnoses among MSM in HIV care in Ontario, Canada.

METHODS

We analyzed data from 2,280 MSM under follow-up from 2006 to 2010 in the Ontario HIV Treatment Network Cohort Study (OCS), a multi-site clinical cohort. We obtained syphilis serology results via record linkage with the provincial public health laboratory. Rates were calculated using Poisson regression.

RESULTS

First syphilis diagnoses occurred at a rate of 2.0 per 100 person-years (95 % CI 1.7, 2.4; 121 cases) whereas the re-diagnosis rate was 7.5 per 100 person-years (95 % CI 6.3, 8.8; 136 cases). We observed higher rates over time and among men who were aged <30 years, receiving care in the two largest urban centers, or had a previous syphilis diagnosis. Syphilis diagnosis was less common among Indigenous men, men with higher CD4 cell counts, and, for first diagnoses only, among men with less than high school education.

CONCLUSIONS

Compared to reported cases in the general male population, incidence of a new syphilis diagnosis was over 300 times greater among HIV-positive MSM but year-to-year changes reflected provincial trends. Re-diagnosis was common, suggesting treatment failure or re-infection. Novel syphilis control efforts are needed among HIV-positive MSM.

Modest rise in chlamydia and gonorrhoea testing did not increase case detection in a clinical HIV cohort in Ontario, Canada

OBJECTIVES

We described patterns of testing for chlamydia and gonorrhoea infection among persons in specialty HIV care in Ontario, Canada, from 2008 to 2011.

METHODS

We analysed data from 3165 participants in the OHTN Cohort Study attending one of seven specialty HIV care clinics. We obtained chlamydia and gonorrhoea test results via record linkage with the provincial public health laboratory. We estimated the proportion of participants who underwent testing annually, the positivity rate among those tested and the proportion diagnosed with chlamydia or gonorrhoea among all under observation. We explored risk factors for testing and diagnosis using multiple logistic regression analysis.

RESULTS

The proportion tested annually rose from 15.2% (95% CI 13.6% to 16.7%) in 2008 to 27.0% (95% CI 25.3% to 28.6%) in 2011 (p<0.0001). Virtually all were urine-based nucleic acid amplification tests. Testing was more common among men who have sex with men (MSM), younger adults, Toronto residents, persons attending primary care clinics and persons who had tested in the previous year or who had more clinic visits in the current year. We observed a decrease in test positivity rates over time. However, the annual proportion diagnosed remained stable and in 2011 this was 0.97% (95% CI 0.61% to 1.3%) and 0.79% (95% CI 0.46% to 1.1%) for chlamydia and gonorrhoea, respectively. Virtually all cases were among MSM.

CONCLUSIONS

Chlamydia and gonorrhoea testing increased over time while test positivity rates declined and the overall proportion diagnosed remained stable, suggesting that the modest increase in testing did not improve case detection.

Impact of the HIV epidemic and Anti-Retroviral Treatment policy on lymphoma incidence and subtypes seen in the Western Cape of South Africa, 2002-2009: preliminary findings of the Tygerberg Lymphoma Study Group

The Tygerberg Lymphoma Study Group was constituted in 2007 to quantify the impact of HIV on the pattern and burden of lymphoma cases in the Western Cape of South Africa which currently has an HIV prevalence of 15%. South Africa has had an Anti-Retroviral Treatment (ART) policy and a roll-out plan since 2004 attaining 31% effective coverage in 2009. This study is designed to qualify and establish the impact of HIV epidemic and the ARV roll-out treatment program on the incidence of HIV Related Lymphoma (HRL). Early data document that despite the ART roll out, cases of HRL are increasing in this geographical location, now accounting for 37% of all lymphomas seen in 2009 which is an increase from 5% in 2002. This is in contrast to trends seen in developed environments following the introduction of ART. Also noted are the emergence of subtypes not previously seen in this location such as Burkitt and plasmablastic lymphomas. Burkitt lymphoma is now the commonest HRL seen in this population followed by diffuse large B-cell lymphoma subtypes. The reasons for this observed increase in HRL are not ascribable to improved diagnostic capacity as the tertiary institute in which these diagnoses are made has had significant expertise in this regard for over a decade. We ascribe this paradoxical finding to an ART treatment environment that is ineffective for a diversity of reasons, paramount of which are poor coverage, late commencement of ART and incomplete viral suppression.

Abiotic stress enhances androgenesis from isolated microspores of some legume species (Fabaceae)

To induce androgenesis in field pea, grass pea and the model legume species Medicago truncatula, isolated microspores of various genotypes of these three species were submitted to a range of abiotic stresses prior to and during their initial culture, in order to stimulate them to divide and form embryos. Some stress agents had a positive effect on androgenesis from the treated microspores. Submission of flower buds to a cold period prior to anther excision or microspore isolation, modifying the osmotic pressure of the medium during initial culture and electroporation of isolated microspores were the three major individual stress agents to have an impact on the efficiency of androgenetic proliferation and subsequent differentiation from the microspores of pea, grass pea and M. truncatula genotypes. A combination of osmotic and electric shocks significantly improved responses from isolated microspores and yielded microcalluses and then calluses, but only few underwent morphogenesis. Further work is under way to improve responses and extend them to other genotypes. The results reported here are, to the best of our knowledge, the first successful results from isolated microspores of these species.

A randomized prospective study on the treatment of intra-articular distal radius fractures: open reduction and internal fixation with dorsal plating versus mini open reduction, percutaneous fixation, and external fixation

PURPOSE

To compare 2 methods of surgical treatment for displaced intra-articular fractures of the distal radius: open reduction and internal fixation with dorsal plating (Pi Plate; Synthes, Paoli, PA) versus mini open reduction with percutaneous K-wire and external fixation.

METHODS

Patients with AO type C intra-articular distal radius fractures were randomized into 2 groups: open reduction and internal fixation and dorsal plating or external fixation and K-wires and mini-open reduction. Patients over the age of 70 years with any associated soft-tissue or skeletal injury to the same limb and pre-existing wrist arthrosis or disability were excluded from the study. Objective, subjective, and radiographic outcomes were assessed at 2 weeks, 4 to 6 weeks, 10 to 12 weeks, 6 months, and 1- and 2-year intervals. The minimum follow-up period was 6 months; the average follow-up period was 18 months. The principal outcome analyzed was the Disabilities of the Arm, Shoulder, and Hand score. Secondary outcomes included grip strength, range of motion, surgical procedure time, complications, and radiographic parameters. The groups were equal with respect to age, gender, fracture subtype, and number of workers' compensation cases.

RESULTS

No significant difference was found in the Disabilities of the Arm, Shoulder, and Hand scores, our primary outcome. The dorsal plate group, however, showed a higher complication rate when compared with the external fixator group. The plate group had significantly longer tourniquet times when compared with the external fixator group. The plate group also had higher levels of pain at 1 year when compared with the external fixator group; however, this equalized after hardware removal. The external fixator group showed an average grip strength of 97% compared with the normal side and 86% in the dorsal plate group.

CONCLUSIONS

At midterm analysis the dorsal plate group showed a significantly higher complication rate compared with the external fixator group; therefore enrollment in the study was terminated. The dorsal plate group also showed statistically significant higher levels of pain, weaker grip strength, and longer surgical and tourniquet times. Based on these results we cannot recommend the use of dorsal plates in treating complex intra-articular fractures of the distal radius.

Coordinated secretion of alkaline phosphatase into serum and intestine in fat-fed rats

BACKGROUND

Fat feeding increases the activity of intestinal alkaline phosphatase in the serum. The mechanism underlying this increase is unknown. Surfactant-like particles (SLP) secreted by enterocytes have been implicated in this phenomenon.

OBJECTIVE

To study the effect of feeding fish oil and protein synthesis inhibitors on alkaline phosphatase activity in serum and in different intestinal fractions.

METHODS

Male albino rats were fed 2 mL of fish oil and were injected cycloheximide or actinomycin D. Alkaline phosphatase activity was determined in the serum and intestinal fractions (SLP, mucosa, muscularis).

RESULT

Feeding fish oil significantly elevated alkaline phosphatase activity in serum (p< 0.001) and intestinal mucosa (p< 0.01). Administration of cycloheximide or actinomycin D significantly reduced alkaline phosphatase activity in serum (p< 0.01) and in intestinal mucosa (p< 0.05). BCIP staining of brush border alkaline phosphatase activity in acrylamide gels yielded similar results.

CONCLUSIONS

These findings suggest a co-ordination between alkaline phosphatase synthesis and its assembly into lipoprotein vesicles, such as SLP, secreted by enterocytes in response to fat feeding.

Rituximab for autoimmune haemophilia: a proposed treatment algorithm

We previously reported durable complete responses following brief courses of rituximab and prednisone with or without cyclophosphamide in four patients with autoimmune haemophilia and inhibitor titres of 5-60 BU. We report here responses to this monoclonal anti-CD20 antibody in four additional patients, including two patients with inhibitor titres >200 BU. Factor VIII levels became normal 2-35weeks after 4 or 8 weekly doses of rituximab, brief courses of prednisone and in one patient immunoglobulin. Complete responses are ongoing at 10 months in two patients. Two patients relapsed: a patient whose initial inhibitor titre was 525 BU relapsed at 3.5 months and a long-term prednisone-dependent patient at 8.5 months. Both responded to second courses of rituximab and prednisone and are in remission. Our experience suggests that rituximab is a safe and effective addition to immunosuppression with prednisone and cyclophosphamide to treat autoimmune haemophilia, and may permit early discontinuation or even avoidance of these potentially toxic agents. High-titre inhibitor patients, however, may require multiple courses of rituximab or the addition of cyclophosphamide. Pending randomized studies, we propose an algorithm based on our experience and other reports for incorporating rituximab in the treatment of this rare disorder.

Synthetic mannosides act as acceptors for mycobacterial α1-6 mannosyltransferase

A series of synthetic mannosides was screened in a cell-free system for their ability to act as acceptor substrates for mycobacterial mannosyltransferases. Evaluation of these compounds demonstrated the incorporation of [14C]Man from GDP-[14C]Man into a radiolabeled organic-soluble fraction and analysis by thin layer chromatography and autoradiography revealed the formation of two radiolabeled products. Each synthetic acceptor was capable of accepting one or two mannose residues, resulting in a major and a minor mannosylated product. Both products from each acceptor were isolated and their mass was confirmed by fast-atom bombardment-mass spectrometry (FABMS). Characterization of each mannosylated product by exo-glycosidase digestion. acetolysis and linkage analysis by gas chromatography mass spectrometry of partially per-O-methylated alditols, revealed only alpha1-6-linked products. In addition. the antibiotic amphomycin selectively inhibited the formation of mannosylated products suggesting polyprenolmonophosphate-mannose (C15 50-P-Man) was the immediate mannose donor in all mannosylation reactions observed. The ability of synthetic disaccharides to act as acceptor substrates in this system, is most likely due to the action of a mycobacterial polyprenol-P-Man:mannan alpha1-6 mannosyltransferase involved in the biosynthesis of linear alpha1-6-linked lipomannan.

Ulnar nerve elongation and excursion in the cubital tunnel after decompression and anterior transposition

We studied the elongation and excursion of cadaveric ulnar nerves during elbow flexion in control conditions and after in situ decompression and anterior subcutaneous transposition. We found that the normal nerve had the greatest elongation (23%) and excursion (14 mm) in the epicondylar groove. Decompression did not alter the excursion, but significantly reduced the elongation in the groove (6%) and increased it proximally (19%). After anterior subcutaneous transposition, the nerve segment which was originally in the groove elongated with elbow extension to the same extent as occurred with the normal nerve during flexion.

Feasibility of partial A2 and A4 pulley excision: residual pulley strength

We investigated residual digital flexor pulley strengths after 75% excision of the A2 and A4 pulleys. For direct pull-off tests, A2 and A4 pulleys from cadaveric fingers were tested by pulling on a loop of flexor digitorum profundus tendon through the pulley. For functional loading tests, fingers were positioned with the metacarpophalangeal joint flexed to 90 degrees for A2 testing, and with the proximal interphalangeal joint in 90 degrees flexion for A4 testing (with all other joints in full extension). Excision of 75% of A2 and A4 pulleys reduced pulley strengths determined by both testing methods. For the functional loading tests, which are more clinically relevant, mean tendon forces at failure after partial excision of A2 and A4 pulleys were 224 and 131 N respectively, which is sufficient to withstand flexor tendon forces expected during activities of daily living.

Passive and active rehabilitation for partial lacerations of the canine flexor digitorum profundus tendon in zone II

The purpose of this study was to compare the effect of unrestricted active versus passive mobilization on the gliding function and structural properties (ultimate load and stiffness) of repaired and nonrepaired canine flexor digitorum profundus tendons following partial laceration at 1 week. Using a radiographic method, normalized tendon gliding of the flexor digitorum profundus tendon adjacent to the metacarpal bone and total joint rotation were shown to be significantly greater in passive than in active tendons. Each group differed from their control group, however, by an average of only 5%. Both rehabilitation (active vs. passive) and treatment (repair vs. nonrepaired) of the partial tendon laceration significantly affected gap formation. Both active rehabilitation and repair of the laceration significantly increased gap formation compared with passive rehabilitation and nonrepair of the partial laceration. Rehabilitation did not significantly affect the normalized ultimate loads and stiffness in the passive and active groups but the nonrepair groups displayed significantly higher ultimate loads and stiffness than the repair groups.

Feasibility of partial A2 and A4 pulley excision: effect on finger flexor tendon biomechanics

We investigated the effect of partial excision of the A2 and A4 digital pulleys, separately and in combination, on finger angular rotation and the energy for finger flexion. Statistically significant decreases in angular rotation resulted only after 50% and 75% excision of A2, A4, or A2 and A4 in combination. Work of flexion trends were weak and none of the changes were statistically significant. Although optimal finger function relies on the integrity of the A2 and A4 pulleys to maintain the efficiency of the digital flexor system, these data suggest that the A2 and A4 pulleys can be excised up to 25%, either separately or in combination, without significant effects on angular rotation. Decreases in total angular range of motion after 50% and 75% pulley excision were small, even for combined pulley excision (9 degrees +/- 3 degrees and 15 degrees +/- 5 degrees [mean +/- SD], respectively), and may be clinically acceptable.