David M Patrick

• MD, FRCPC, MHSc
• Professor at University of British Columbia

Antibiotics are among the most used therapeutics in primary care, and while their benefits are clear, the potential harms related to adverse drug events (ADEs) cannot be ignored. We outline the creation of a comprehensive list of diagnostic codes describing antibiotic-associated ADEs resulting in presentations to acute care hospitals. Methods: Prev...

Background Infant antibiotic use is associated with increased risk of asthma. We examined the population impact of antibiotic exposure in the first year of life on the burden of pediatric asthma in British Columbia, Canada, using simulation modeling. Methods We performed a Bayesian meta-analysis of empirical studies to construct dose-response equa...

Background This study follows published associations in BC to 2014 (updated in 2019) to model the predicted incidence of asthma in BC children attributable to antibiotic use within the context of reduced antibiotic use and increased breastfeeding in BC infants from 2000 to 2019. Methods A population-based ecological study was conducted in BC from...

Background: Infant antibiotic use is associated with increased risk of asthma. We examined the population impact of antibiotic exposure in the first year of life on the burden of pediatric asthma in British Columbia, Canada, using simulation modeling. Methods: We performed a Bayesian meta-analysis of empirical studies to construct dose-response equ...

Patients’ expectations are a major contributor to the unnecessary prescribing of antibiotics, yet limited research has examined how physicians can calibrate these expectations. The studies we conducted tested how varying messages could impact patients’ expectations for antibiotics and their experience of medical appointments. All the participants r...

Background Urinary tract infections (UTI) are responsible for a significant portion of female, outpatient antibiotic prescriptions. Especially true in uncomplicated cases, where symptoms remain the cornerstone of diagnosis, ensuring the optimal choice of agent, dose and duration may mitigate future bacterial resistance, and lower the likelihood of...

Rationale Acute respiratory distress syndrome (ARDS) is a life-threatening critical care syndrome commonly associated with infections such as COVID-19, influenza, and bacterial pneumonia. Ongoing research aims to improve our understanding of ARDS, including its molecular mechanisms, individualized treatment options, and potential interventions to r...

Background Widespread human-to-human transmission of the severe acute respiratory syndrome coronavirus two (SARS-CoV-2) stems from a strong affinity for the cellular receptor angiotensin converting enzyme two (ACE2). We investigate the relationship between a patient’s nasopharyngeal ACE2 transcription and secondary transmission within a series of c...

Many COVID-19 survivors have post-COVID-19 conditions, and females are at a higher risk. We sought to determine (1) how protein levels change from acute to post-COVID-19 conditions, (2) whether females have a plasma protein signature different from that of males, and (3) which biological pathways are associated with COVID-19 when compared to restri...

Background Antibiotics remain the primary treatment for community acquired pneumonia (CAP), however rising rates of antimicrobial resistance may jeopardize their future efficacy. With higher rates of disease reported in the youngest populations, effective treatment courses for pediatric pneumonia are of paramount importance. This study is the first...

Background This retrospective cohort study is the first in North America to examine population-level appropriate antibiotic use for community-acquired pneumonia (CAP) in older adults, by agent, dose and duration. With the highest rates of CAP reported in the elderly populations, appropriate antibiotic use is essential to improve clinical outcomes....

The COVID-19 pandemic has affected all Canadian families, with some impacted differently than others. Our study aims to: (1) determine the prevalence and transmission of SARS-CoV-2 infection among Canadian families, (2) identify predictors of infection susceptibility and (3) identify health and psychosocial impacts of the COVID-19 pandemic. This st...

Background Vaccination helps prevent SARS-CoV-2 infection and severe COVID-19. However, vaccine-induced humoral immune responses vary among individuals and wane over time. We aimed to describe the SARS-CoV-2 anti-spike IgG antibody response to vaccination and identify health and demographic factors associated with this response among children and a...

Background Enteric infections and their chronic sequelae are a major cause of disability and death. Despite the increasing use of administrative health data in measuring the burden of chronic diseases in the population, there is a lack of validated International Classification of Disease (ICD) code-based case definitions, particularly in the Canadi...

Background: Omicron is the current predominant variant of concern of SARS-CoV-2. We hypothesized that vaccination alters outcomes of patients hospitalized with COVID-19 during the Omicron wave and that these patients have different characteristics and outcomes than in previous waves. Methods: This is a substudy of the Host Response Mediators in...

Introduction: Allergic conditions, such as asthma, hay fever and eczema, are some of the most common conditions impacting children globally. There is a strong incentive to study their determinants to improve their prevention. Asthma, hay fever and eczema are influenced through the same immunological pathway and often copresent in children ('the at...

Background Widespread human-to-human transmission of the severe acute respiratory syndrome coronavirus two (SARS-CoV-2) stems from a strong affinity for the cellular receptor angiotensin converting enzyme two (ACE2). We investigate the relationship between a patient’s nasopharyngeal ACE2 transcription and secondary transmission within a series of c...

Background Early antibiotic exposure is linked to persistent disruption of the infant gut microbiome and subsequent elevated pediatric asthma risk. Breastfeeding acts as a primary modulator of the gut microbiome during early life, but its effect on asthma development has remained unclear. Methods We harnessed the CHILD cohort to interrogate the in...

We assessed patterns of enteric infections caused by 14 pathogens, in a longitudinal cohort study of sequelae in British Columbia (BC) Canada, 2005–2014. Our population cohort of 5.8 million individuals was followed for an average of 7.5 years/person; during this time, 40 523 individuals experienced 42 308 incident laboratory-confirmed, provinciall...

Background The COVID-19 pandemic is affecting all Canadian families, with some impacted differently than others. Our study aims to: 1) determine the prevalence and transmission of SARS-CoV-2 infection among Canadian families, 2) identify predictors of infection susceptibility and severity of SARS-CoV-2 and 3) identify health and psychosocial impact...

While literature indicates that municipal rat management approaches are often unsuccessful, a lack of research comparing strategies makes the breadth of opportunities and challenges associated with different approaches uncertain. Here, we explored the municipal rat management policies and programs in seven cities in the United States of America. Ra...

The COVID-19 pandemic affected access to care, and the associated public health measures influenced the transmission of other infectious diseases. The pandemic has dramatically changed antibiotic prescribing in the community. We aimed to determine the impact of the COVID-19 pandemic and the resulting control measures on oral antibiotic prescribing...

Objectives: To determine whether angiotensin receptor blockers (ARBs) or angiotensin-converting enzyme (ACE) inhibitors are associated with improved outcomes in hospitalized patients with COVID-19 according to sex and to report sex-related differences in renin-angiotensin system (RAS) components. Design: Prospective observational cohort study co...

Background The Canadian COVID-19 immunization strategy deferred second doses and allowed mixed schedules. We compared two-dose vaccine effectiveness (VE) by vaccine type (mRNA and/or ChAdOx1), interval between doses, and time since second dose in two of Canada’s larger provinces. Methods Two-dose VE against SARS-CoV-2 infection or hospitalization...

Background: There have been multiple waves in the COVID-19 pandemic in many countries. We sought to compare mortality and respiratory, cardiovascular and renal dysfunction between waves in 3 Canadian provinces. Methods: We conducted a substudy of the ARBs CORONA I study, a multicentre Canadian pragmatic observational cohort study that examined t...

Objectives Invasive pneumococcal disease (IPD) and a variety of clinical syndromes caused by pneumococci, such as acute otitis media (AOM), acute sinusitis (AS), and community-acquired pneumonia (CAP), cause a substantial burden on healthcare systems. Few studies have explored the short-term financial burden of pneumococcal disease after the 13-val...

To sustainably control urban rat infestations, management efforts need to encompass large areas of urban centers. Therefore, the objective of this review and narrative synthesis was to collate what is known about municipal-scale rat management. We explored the management frameworks that have been used at a large scale in cities and we describe the...

We investigate the diagnostic accuracy and predictive value of finger prick capillary dried blood spot (DBS) samples tested by a quantitative multiplex anti-immuno-globulin G (IgG) assay to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies after infection or vaccination. This cross-sectional study involved participants...

The host response to COVID-19 pathophysiology over the first few days of infection remains largely unclear, especially the mechanisms in the blood compartment. We report on a longitudinal proteomic analysis of acute-phase COVID-19 patients, for which we used blood plasma, multiple reaction monitoring with internal standards, and data-independent ac...

Introduction: In British Columbia, Canada, most adults 50-69 years old became SARS-CoV-2 vaccine-eligible in April 2021, with ChAdOx1 restricted to ≥55-year-olds and second doses deferred ≥6 weeks to optimize single-dose coverage. Methods: Among adults 50-69-years-old, single-dose mRNA and ChAdOx1 VE against SARS-CoV-2 infection and hospitalizat...

Background Pneumonia is a leading cause of morbidity and mortality globally. We determined the impact of 13-valent pneumococcal conjugate vaccine (PCV13) use on community-acquired pneumonia (CAP) rates eight years after the vaccine was introduced in the infant immunization program. Methods Using diagnostic codes from administrative databases, we c...

Background Antimicrobials remain among the most prescribed medications in Canada, with over 90% prescribed in outpatient settings. Older adults (aged ≥65 years) prescribed antimicrobials are particularly vulnerable to adverse drug events and antimicrobial resistance. This study compared annual rates of indication-associated, outpatient prescribing...

Antimicrobials are among the most prescribed medications in Canada, with over 90% of antibiotics prescribed in outpatient settings. Seniors prescribed antimicrobials are particularly vulnerable to adverse drug events and antimicrobial resistance. The extent of inappropriate antibiotic prescribing in outpatient Canadian medical practice, and the pot...

Despite decades of stewardship efforts to combat antimicrobial resistance and quantify changes in use, the quality of antibiotic use in British Columbia (BC) remains unknown. As the overuse and misuse of antibiotics drives antibiotic resistance, it is imperative to expand surveillance efforts to examine the quality of antibiotic prescriptions. In l...

Background The Canadian COVID-19 immunization strategy deferred second doses and allowed mixed schedules. We compared two-dose vaccine effectiveness (VE) by vaccine type (mRNA and/or ChAdOx1), interval between doses, and time since second dose in two of Canada’s larger provinces. Methods Two-dose VE against infections and hospitalizations due to S...

Background Acute kidney injury (AKI) is a potentially fatal complication of Coronavirus Disease-2019 (COVID-19). Binding of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the virus responsible for COVID-19, to its viral receptor, angiotensin converting enzyme 2 (ACE2), results in viral entry and may cause AKI. Objectives We perf...

Introduction: In randomized controlled trials, single-dose efficacy against SARS-CoV-2 illness exceeded 90% for mRNA vaccines (BNT162b2 and mRNA-1273), and 75% for ChAdOx1. In British Columbia (BC), Canada second doses were deferred up to 16 weeks and ChAdOx1 was only initially recommended for adults 55 years of age and older. We compared single-do...

Background: With 90% of all antibiotics in Canada being used in the community setting, tracking outpatient prescribing is integral to mitigate the issue of antimicrobial resistance. In 2005, a provincial programme was launched in British Columbia (BC) to disseminate information regarding the judicious use of antibiotics. These efforts include educ...

Importance: Measuring humoral immunogenicity of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) vaccines and finding population-level correlates of protection against coronavirus disease (COVID-19) presents an immediate challenge to public health practitioners. Objective: To study the diagnostic accuracy and predictive value of finger...

Background Hepatitis C virus (HCV) causes life-threatening chronic infections. Implementation of novel, economical or widely available screening tools can help detect unidentified cases and facilitate their linkage to care. We investigated the relationship between chronic HCV infection and a potential complete blood count biomarker (the monocyte-to...

Introduction: Randomized-controlled trials of mRNA vaccine protection against SARS-CoV-2 included few elderly participants. We assess single-dose mRNA vaccine effectiveness (VE) in adults ≥70-years-old in British Columbia (BC), Canada where second doses were deferred by up to 16 weeks and where a spring 2021 wave uniquely included co-dominant circ...

Introduction: Randomized-controlled trials of mRNA vaccine protection against SARS-CoV-2 included relatively few elderly participants. We assess singe-dose mRNA vaccine effectiveness (VE) in adults ≥70-years-old in British Columbia (BC), Canada where the second dose was deferred by up to 16 weeks and where a spring 2021 wave uniquely included co-do...

Purpose : To estimate the risk of tuberculosis (TB)-associated depression. A second aim was to estimate the extent to which any increased risk of depression among TB patients may be mediated by the length of hospital length stay (LOS) Methods : Retrospective cohort study of linked healthcare claims and public health surveillance data. Our primary...

Rats evoke public health and economic concern in cities globally. Rapid urbanization exacerbates pre-existing rat problems, requiring the development and adoption of more effective methods of prevention, monitoring and mitigation. While previous studies have indicated that city-wide municipal management approaches often fail, such outcomes are ofte...

Background: Numerous studies have characterized the 13-valent pneumococcal conjugate vaccine (PCV13) programme's beneficial effects on acute otitis media (AOM) and acute sinusitis (AS) rates in children; however, few studies have examined the impact on adults. Objectives: This retrospective cohort study evaluates the overall effect of the PCV13...

Objectives To examine the aggregate rates of antibiotic use at population level and compare these rates over time against historical averages to identify the effect of SARS-CoV-2 and the resulting control measures, upon community prescribing. Methods We collected antibiotic prescriptions and physician office visits from January 1, 2016 to July 21,...

Objective Our objective was to compare patterns of dental antibiotic prescribing in Australia, England, and North America (United States and British Columbia, Canada). Design Population-level analysis of antibiotic prescription. Setting Outpatient prescribing by dentists in 2017. Participants Patients receiving an antibiotic dispensed by an outp...

Background: Angiotensin converting enzyme 2 (ACE2) protein serves as the host receptor for SARS-CoV-2, with a critical role in viral infection. We aim to understand population level variation of nasopharyngeal ACE2 transcription in people tested for COVID-19 and the relationship between ACE2 transcription and SARS-CoV-2 viral load, while adjusting...

BACKGROUND Angiotensin receptor blockers (ARBs) and/or angiotensin converting enzyme (ACE) inhibitors could alter mortality of COVID-19, but existing meta-analyses which combined crude and adjusted results may be confounded by comorbidities being more common in ARBs/ACE inhibitors users. METHODS We searched PubMed/MEDLINE/Embase for cohort studies...

Background Current epidemiological evidence of post-TB airway disease is largely cross-sectional and derived from high-TB-incidence settings. We present the first cohort study of post-TB airway disease in a low-TB-incidence setting. Aims (1) analyze the risk of airway disease by respiratory TB, (2) assess potential unmeasured confounding between T...

Wild waterbirds are reservoir hosts for avian influenza viruses (AIV), which can cause devastating outbreaks in multiple species, making them a focus for surveillance efforts. Traditional AIV surveillance involves direct sampling of live or dead birds, but environmental substrates present an alternative sample for surveillance. Environmental sampli...

Background Pneumonia is a leading cause of hospitalization and in-patient mortality globally. We determined the impact of 13-valent pneumococcal conjugate vaccine (PCV13) use on all-cause pneumonia hospitalization rates eight years after the vaccine was introduced in British Columbia, Canada. Methods Routine administrative databases, such as, hosp...

Background Antimicrobial resistance continues to jeopardize the future of modern medicine; as 92% of all antibiotics are used in the community, it is imperative to parse outpatient prescribing. In British Columbia (BC), efforts to curb the use of these essential medications have included: stewardship campaigns, practitioner guidelines, and vaccine...

Background Antibiotic resistance is recognised as a major public health burden. Dentists overprescribe antibiotics and prescribe for unnecessary indications. Tracking and investigating prescribing practices by healthcare professionals provides insights needed to inform targeted antibiotic stewardship interventions. It is unclear how dental antibiot...

In the event of the current COVID-19 pandemic and in preparation for future pandemics, open science can support mission-oriented research and development, as well as commercialization. Open science shares skills and resources across sectors; avoids duplication and provides the basis for rapid and effective validation due to full transparency. It is...

SARS-CoV-2 enters cells by binding to angiotensin-converting enzyme 2 (ACE2), and COVID-19 infection may therefore induce changes in the renin-angiotensin system (RAS). To determine the effects of COVID-19 on plasma RAS components, we measured plasma ACE, ACE2, and angiotensins I, (1-7), and II in 46 adults with COVID-19 at hospital admission and o...

Antimicrobial resistance (AMR), a central health challenge of the twenty first century, poses substantial population health risks, with deaths currently estimated to be around 700,000 per year globally. The international community has signaled its commitment to exploring and implementing effective policy responses to AMR, with a Global Action Plan...

Introduction The COVID-19 epidemic grows and there are clinical trials of antivirals. There is an opportunity to complement these trials with investigation of angiotensin II type 1 receptor blockers (ARBs) because an ARB (losartan) was effective in murine influenza pneumonia. Methods and analysis Our innovative design includes: ARBs; alignment wit...

Background Angiotensin converting enzyme 2 ( ACE2 ) serves as the host receptor for SARS-CoV-2, with a critical role in viral infection. We aim to understand population level variation of nasopharyngeal ACE2 expression in people tested for COVID-19 and the relationship between ACE2 expression and SARS-CoV-2 viral RNA load, while adjusting for expre...

Leptospira interrogans is one of the most important zoonotic pathogens globally. In urban settings, Norway rats (Rattus norvegicus) are important reservoirs of L. interrogans, but it is unclear how this bacterium is transmitted among rats. Both environmental features and rat population density may determine the prevalence of this pathogen in rat po...

Background A significant reduction in invasive pneumococcal disease (IPD) has been reported, across all ages, following the implementation of 7-valent conjugate pneumococcal vaccine (PCV7) globally, as part of infant immunization programs. We explored the additional impact of PCV13 on IPD over a 14-year period. Methods Using provincial laboratory...

Introduction Over one in eight Canadians is affected by a foodborne infection annually; however, the long-term consequences, including the risks and costs of sequelae, are unclear. We aim to estimate the health burden and direct costs of 14 infections commonly transmitted by food, considering the acute illness and subsequent sequelae and mortality,...

Urban Norway rats (Rattus norvegicus) carry several pathogens transmissible to people. However, pathogen prevalence can vary across fine spatial scales (i.e., by city block). Using a population genomics approach, we sought to describe rat movement patterns across an urban landscape, and to evaluate whether these patterns align with pathogen distrib...

Background: The province of British Columbia (BC) has been recognized for successful SARS-CoV-2 control, with surveillance data showing amongst the lowest case and death rates in Canada. We estimate sero-prevalence for two periods flanking the start (March) and end (May) of first-wave mitigation measures in BC. Methods: Serial cross-sectional sampl...

Objective To compare non-tuberculosis (non-TB)-cause mortality risk overall and cause-specific mortality risks within the immigrant population of British Columbia (BC) with and without TB diagnosis through time-dependent Cox regressions.Methods All people immigrating to BC during 1985–2015 (N = 1,030,873) were included with n = 2435 TB patients, an...

Background There is increasing evidence of prodromal multiple sclerosis (MS). Objective The aim of this study was to determine whether fatigue, sleep disorders, anaemia or pain form part of the MS prodrome. Methods This population-based matched cohort study used linked administrative and clinical databases in British Columbia, Canada. The odds of...

Background Childhood asthma incidence is decreasing in some parts of Europe and North America. Antibiotic use in infancy has been associated with increased asthma risk. In the present study, we tested the hypothesis that decreases in asthma incidence are linked to reduced antibiotic prescribing and mediated by changes in the gut bacterial community...

Background Pneumococcal conjugate vaccines have substantially reduced the incidence of invasive pneumococcal disease (IPD); however, the impact of the vaccine on non-vaccine serotypes (NVT) remains unclear. We evaluated the effect of PCV13 use in British Columbia, Canada. Methods The annual incidence following implementation of PCV7 (September 200...

Background Early-life exposure to antibiotics is associated with childhood asthma. We previously reported that a dramatic drop in infant antibiotic use is correlated with a decline in asthma incidence in children in British Columbia (BC). This study aims to see whether antibiotic exposure predicts asthma at a fine geographic scale after adjustment...

Background Many jurisdictions report a significant reduction in invasive pneumococcal disease (IPD) in adults following implementation of the pneumococcal conjugate vaccines, 7-valent (PCV7) and 13-valent (PCV13) in childhood immunization programs. This study evaluates the indirect effect of conjugate vaccines on IPD in British Columbia, Canada ove...

Background Antibiotic prescribing in pediatric care is highly prevalent, and quite often children are prescribed for conditions which are commonly self-limiting and viral in etiology. The purpose of this study was to examine the scope of pediatric antibiotic prescribing by indication, from 2013 to 2016, and identify potential new targets for provin...

Background Antibiotic prescribing in pediatric care is highly prevalent. Often children are prescribed antibiotics for conditions that are commonly self-limiting and viral in etiology such as upper respiratory tract infections. The purpose of this study was to examine the scope of pediatric antibiotic prescribing in British Columbia from 2013 to 20...

Background A significant reduction in invasive pneumococcal disease (IPD) has been reported following implementation of the 7-valent pneumococcal conjugate vaccine (PCV7) infant immunization program, but not much has been reported after introduction of the 13-valent vaccine (PCV13). This study represents the effect of PCV13 on IPD in British Columb...

Objective In 2005, the Do Bugs Need Drugs (DBND) program was imported to British Columbia (BC) from Alberta with the goal of reducing unnecessary antibiotic use in the community. The objective of this study was to estimate the impact of the program on antibiotic-associated costs and cost-benefit. Methods We used data on antibiotic prescription and...

A random-sequence peptide microarray can interrogate serum antibodies in a broad, unbiased fashion to generate disease-specific immunosignatures. This approach has been applied to cancer detection, diagnosis of infections, and interrogation of vaccine response. We hypothesized that there is an immunosignature specific to ME/CFS and that this could...

Objective: To explore whether there are observable physician characteristics associated with antibiotic prescribing for pediatric respiratory tract infections (RTIs). Design: Population-based cohort study using a hierarchical generalized linear mixed-model analysis. Setting: British Columbia. Participants: All pediatric visits for RTIs betwe...

Myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) is a syndrome of unknown etiology characterized by profound fatigue exacerbated by physical activity, also known as post-exertional malaise (PEM). Previously, we did not detect evidence of immune dysregulation or virus reactivation outside of PEM periods. Here we sought to determine whet...

Understanding the local ecology of urban Norway rats (Rattus norevgicus) is necessary to inform effective rat mitigation strategies. While Capture-Mark-Recapture (CMR) methods can be used to acquire such ecological information (e.g., abundance, movement patterns, and habitat use), these techniques assume that all individuals of the study population...

Introduction Urinary tract infections (UTI) are common community-based bacterial infections. Empiric antibiotic recommendations are guided by local resistance rates. Previous research suggests that cultures are overused for uncomplicated cystitis, but practice patterns have not been described in detail. Variations in culturing have implications for...

A list of the data files and variables requested in the data extract. (DOCX)

Norway and black rats (Rattus norvegicus and Rattus rattus) are ubiquitous urban pests, inhabiting cities worldwide. Despite their close association with people, urban rats remain difficult to control. This can be partly attributed to a general lack of information on basic rat ecology to inform management efforts. In this systematic review and narr...