Pharmacogenetics of aminoglycoside-related ototoxicity: a systematic review.

BACKGROUND: Aminoglycosides (AGs) are important antibiotics in the treatment of Gram-negative sepsis. However, they are associated with the risk of irreversible sensorineural hearing loss (SNHL). Several genetic variants have been implicated in the development of ototoxicity. OBJECTIVES: To evaluate the pharmacogenetic determinants of AG-related ototoxicity. METHODS: This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses and was registered on Prospero (CRD42022337769). In Dec 2022, PubMed, Cochrane Library, Embase and MEDLINE were searched. Included studies were those reporting original data on the effect of the AG-exposed patient's genome on the development of ototoxicity. RESULTS: Of 10 202 studies, 31 met the inclusion criteria. Twenty-nine studies focused on the mitochondrial genome, while two studied the nuclear genome. One study of neonates found that 30% of those with the m.1555A > G variant failed hearing screening after AG exposure (level 2 evidence). Seventeen additional studies found the m.1555A > G variant was associated with high penetrance (up to 100%) of SNHL after AG exposure (level 3-4 evidence). Nine studies of m.1494C > T found the penetrance of AG-related SNHL to be up to 40%; however, this variant was also identified in those with SNHL without AG exposure (level 3-4 evidence). The variants m.1005T > C and m.1095T > C may be associated with AG-related SNHL; however, further studies are needed. CONCLUSIONS: This review found that the m.1555A > G and m.1494C > T variants in the MT-RNR1 gene have the strongest evidence in the development of AG-related SNHL, although study quality was limited (level 2-4). These variants were associated with high penetrance of a SNHL phenotype following AG exposure.

Building on existing tools to improve chronic disease prevention and screening in public health: a cluster randomized trial.

BACKGROUND: The BETTER (Building on Existing Tools to Improve Chronic Disease Prevention and Screening in Primary Care) intervention was designed to integrate the approach to chronic disease prevention and screening in primary care and demonstrated effective in a previous randomized trial. METHODS: We tested the effectiveness of the BETTER HEALTH intervention, a public health adaptation of BETTER, at improving participation in chronic disease prevention and screening actions for residents of low-income neighbourhoods in a cluster randomized trial, with ten low-income neighbourhoods in Durham Region Ontario randomized to immediate intervention vs. wait-list. The unit of analysis was the individual, and eligible participants were adults age 40-64 years residing in the neighbourhoods. Public health nurses trained as "prevention practitioners" held one prevention-focused visit with each participant. They provided participants with a tailored prevention prescription and supported them to set health-related goals. The primary outcome was a composite index: the number of evidence-based actions achieved at six months as a proportion of those for which participants were eligible at baseline. RESULTS: Of 126 participants (60 in immediate arm; 66 in wait-list arm), 125 were included in analyses (1 participant withdrew consent). In both arms, participants were eligible for a mean of 8.6 actions at baseline. At follow-up, participants in the immediate intervention arm met 64.5% of actions for which they were eligible versus 42.1% in the wait-list arm (rate ratio 1.53 [95% confidence interval 1.22-1.84]). CONCLUSION: Public health nurses using the BETTER HEALTH intervention led to a higher proportion of identified evidence-based prevention and screening actions achieved at six months for people living with socioeconomic disadvantage. TRIAL REGISTRATION: NCT03052959 , registered February 10, 2017.

Stage of colorectal cancer diagnosis for immigrants: a population-based retrospective cohort study in Ontario, Canada.

BACKGROUND: Colorectal cancer (CRC) is the second most common cause of cancer death in Canada. Immigrants in Ontario, Canada's most populous province, are known to have lower rates of CRC screening, but differences in stage of CRC diagnosis are not known. METHODS: We utilized linked administrative databases to compare early (stage I-II) versus late (stage III-IV) stage of CRC diagnosis for immigrants versus long-term residents among patients diagnosed in Ontario between 2012 and 2017 (n = 37,717) and examined the association of immigration-related, sociodemographic, and healthcare-related factors with stage. RESULTS: Almost 45% of those with CRC were diagnosed at a late stage. Immigrants were slightly more likely to be diagnosed at a late stage than their long-term resident counterparts [Adjusted relative risks (ARRs) 1.06 (95% CI 1.02-1.10)], but after adjusting for age and sex, this difference was no longer significant. In fully adjusted models, we observed a higher likelihood of late-stage diagnosis for people with the fewest co-morbidities (ARR 0.86 [95% CI 0.83-0.89]) and those with no visits to primary care (versus a high level of continuity of care) [ARR 1.07 (95% CI 1.03-1.12)]. CONCLUSION: Immigrants were not more likely to have a late-stage CRC diagnosis after adjusting for relevant factors, but access to primary care and healthcare contact was significantly associated with diagnostic stage. IMPACT: Attachment to a primary care provider who provides regular preventive care may play a role in more favorable stage at diagnosis for CRC and thus should be a healthcare system priority.

Risk of infertility in female adolescents and young adults with cancer: a population-based cohort study.

STUDY QUESTION: Do female adolescents and young adults (AYAs) with cancer have a higher risk of subsequent infertility diagnosis than AYAs without cancer? SUMMARY ANSWER: Female AYAs with breast, hematological, thyroid and melanoma cancer have a higher risk of subsequent infertility diagnosis. WHAT IS KNOWN ALREADY: Cancer therapies have improved substantially, leading to dramatic increases in survival. As survival improves, there is an increasing emphasis on optimizing the quality of life among cancer survivors. Many cancer therapies increase the risk of infertility, but we lack population-based studies that quantify the risk of subsequent infertility diagnosis in female AYAs with non-gynecological cancers. The literature is limited to population-based studies comparing pregnancy or birth rates after cancer against unexposed women, or smaller studies using markers of the ovarian reserve as a proxy of infertility among female survivors of cancer. STUDY DESIGN, SIZE, DURATION: We conducted a population-based cohort study using universal health care databases in the province of Ontario, Canada. Using data from the Ontario Cancer Registry, we identified all women 15-39 years of age diagnosed with the most common cancers in AYAs (brain, breast, colorectal, leukemia, Hodgkin lymphoma, non-Hodgkin lymphoma, thyroid and melanoma) from 1992 to 2011 who lived at least 5 years recurrence-free (Exposed, n = 14,316). Women with a tubal ligation, bilateral oophorectomy or hysterectomy previous to their cancer diagnosis were excluded. We matched each exposed woman by age, census subdivision, and parity to five randomly selected unexposed women (n = 60,975) and followed subjects until 31 December 2016. PARTICIPANTS/MATERIALS, SETTING, METHODS: Infertility diagnosis after 1 year of cancer was identified using information on physician billing codes through the Ontario Health Insurance Plan database (ICD-9 628). Modified Poisson regression models were used to assess the risk of infertility diagnosis (relative risk, RR) adjusted for income quintile and further stratified by parity at the time of cancer diagnosis (nulliparous and parous). MAIN RESULTS AND THE ROLE OF CHANCE: Mean age at cancer diagnosis was 31.4 years. Overall, the proportion of infertility diagnosis was higher in cancer survivors compared to unexposed women. Mean age of infertility diagnosis was similar among cancer survivors and unexposed women (34.8 years and 34.9 years, respectively). The overall risk of infertility diagnosis was higher in cancer survivors (RR 1.30; 95% CI 1.23-1.37). Differences in infertility risk varied by type of cancer. Survivors of breast cancer (RR 1.46; 95% CI 1.30-1.65), leukemia (RR 1.56; 95% CI 1.09-2.22), Hodgkin lymphoma (RR 1.49; 95% CI 1.28-1.74), non-Hodgkin lymphoma (RR 1.42; 95% CI 1.14, 1.76), thyroid cancer (RR 1.20; 95% CI 1.10-1.30) and melanoma (RR 1.17; 95% CI 1.01, 1.35) had a higher risk of infertility diagnosis compared to women without cancer. After stratification by parity, the association remained in nulliparous women survivors of breast cancer, leukemia, lymphoma and melanoma, whereas it was attenuated in parous women. In survivors of thyroid cancer, the association remained statistically significant in both nulliparous and parous women. In survivors of brain or colorectal cancer, the association was not significant, overall or after stratification by parity. LIMITATIONS, REASONS FOR CAUTION: Non-biological factors that may influence the likelihood of seeking a fertility assessment may not be captured in administrative databases. The effects of additional risk factors, including cancer treatment, which may modify the associations, need to be assessed in future studies. WIDER IMPLICATIONS OF THE FINDINGS: Reproductive health surveillance in female AYAs with cancer is a priority, especially those with breast cancer, leukemia and lymphoma. Our finding of a potential effects of thyroid cancer (subject to over-diagnosis) and, to a lesser extent, melanoma need to be further studied, and, if an effect is confirmed, possible mechanisms need to be elucidated. STUDY FUNDING/COMPETING INTEREST(S): Funding was provided by the Faculty of Health Sciences and Department of Obstetrics and Gynecology, Queen's University. There are no competing interests to declare. TRIAL REGISTRATION NUMBER: N/A.

A pan-Canadian prospective study of young women with breast cancer: the rationale and protocol design for the RUBY study.

Introduction: The understanding of the biology and epidemiology of, and the optimal therapeutic strategies for, breast cancer (bca) in younger women is limited. We present the rationale, design, and initial recruitment of Reducing the Burden of Breast Cancer in Young Women (ruby), a unique national prospective cohort study designed to examine the diagnosis, treatment, quality of life, and outcomes from the time of diagnosis for young women with bca. Methods: Over a 4-year period at 33 sites across Canada, the ruby study will use a local and virtual recruitment model to enrol 1200 women with bca who are 40 years of age or younger at the time of diagnosis, before initiation of any treatment. At a minimum, comprehensive patient, tumour, and treatment data will be collected to evaluate recurrence and survival. Patients may opt to complete patient-reported questionnaires, to provide blood and tumour samples, and to be contacted for future research, forming the core dataset from which 4 subprojects evaluating genetics, lifestyle factors, fertility, and local management or delivery of care will be performed. Summary: The ruby study will be the most comprehensive repository of data, biospecimens, and patient-reported outcomes ever collected with respect to young women with bca from the time of diagnosis, enabling research unique to that population now and into the future. This research model could be used for other oncology settings in Canada.

Does the presence of an intact primary increase the risk of nonelective colorectal surgery in patients treated with bevacizumab?

AIM: In patients with incurable metastatic colorectal cancer (mCRC), resection of the primary tumour is debated; however, patients with intact primaries may be at a higher risk of complications requiring surgery when receiving treatment with bevacizumab. Our aim was to estimate the risk of nonelective colorectal surgery in patients undergoing bevacizumab therapy for mCRC and evaluate the association between intact primary tumours and risk of nonelective surgery. METHOD: We designed a population-based, retrospective cohort study using administrative and cancer registry data in Ontario, Canada. We included patients with mCRC who received bevacizumab from 1 January 2008 to 31 December 2014. The primary outcome was nonelective colorectal surgery after initiation of bevacizumab. We determined the cumulative incidence of nonelective colorectal surgery among patients with previously resected and unresected primaries, accounting for the competing risk of death. We explored the relationship between previous resection of the primary and need for nonelective surgery using a cause-specific hazards model, controlling for patient, tumour and treatment factors. RESULTS: We identified 1840 (32.7%) patients with intact primaries and 3784 (67.3%) patients with prior resection. The cumulative incidence of nonelective surgery 1 year after initiating bevacizumab for all patients was 3.9% (95% CI 3.4-4.5%). One-year cumulative incidence was higher in those with intact primaries than in those with resected primaries (6.1% vs 2.9%, P < 0.0001). After adjustment, an intact primary remained strongly associated with nonelective colorectal surgery (hazard ratio = 2.89, 95% CI 2.32-3.61; P < 0.0001). CONCLUSION: Bevacizumab is associated with a low but meaningful risk for serious gastrointestinal complications, necessitating vigilance, particularly among patients with an intact primary tumour.

Perioperative outcomes of women with and without class III obesity undergoing hysterectomy for endometrioid endometrial cancer: A population-based study.

OBJECTIVE: Population-based data on perioperative complications among women with endometrial cancer and severe obesity are lacking. We evaluated 30-day complication rates among women with and without class III obesity (body mass index ≥ 40 kg/m2) undergoing primary surgical management for endometrioid endometrial cancer (EEC), and how outcomes differed according to surgical approach (open vs. minimally invasive). METHODS: We performed a retrospective population-based cohort study of women with EEC undergoing hysterectomy in Ontario, Canada, between 2006 and 2015. We evaluated perioperative complications in the whole cohort, and in a 1:1 matched analysis using hard and propensity score matching to ensure similar distributions of patient, tumour, provider and institution-level factors between women with and without class III obesity (identified using a surgical billing code). The primary outcome of interest was the 30-day perioperative complication rate. RESULTS: 12,112 women met inclusion criteria; 2697 (22.3%) had class III obesity. We matched 2320 (86%) women with class III obesity to those without. The composite complication rate was significantly higher among women with class III obesity (23.2% vs. 18.4%, standardized mean difference [SMD] = 0.12), primarily due to wound infection/disruption (12.1% vs. 6.2%). There was no difference in outcomes for women with and without class III obesity when a minimally invasive approach was used. CONCLUSIONS: Wound infection/disruption was increased for women with class III obesity compared to women without. Otherwise, perioperative complications were similar between the matched pairs. When minimally invasive approaches were used, women with class III obesity had a similar risk of complications as women without obesity.

Early urinary catheter removal after rectal surgery: systematic review and meta-analysis.

BACKGROUND: Urinary catheters are placed after rectal surgery to prevent urinary retention, but prolonged use may increase the risk of urinary tract infection (UTI). This review evaluated the non-inferiority of early urinary catheter removal compared with late removal for acute urinary retention risk after rectal surgery. METHODS: MEDLINE, Embase and the Cochrane Central Register of Controlled Trials were searched from January 1980 to February 2019. RCTs comparing early versus late catheter removal after rectal surgery were eligible. Primary outcomes were acute urinary retention and UTI; the secondary outcome was length of hospital stay. Early catheter removal was defined as removal up to 2 days after surgery, with late removal after postoperative day 2. The non-inferiority margin from an included trial was used for analysis of change in urinary retention (ΔNI = 15 per cent). Pooled estimates of risk differences (RDs) were derived from random-effects models. Risk of bias was assessed using a modified Cochrane risk-of-bias tool. RESULTS: Four trials were included, consisting of 409 patients. There was insufficient evidence to conclude non-inferiority of early versus late catheter removal for acute urinary retention (RD 9 (90 per cent c.i. -1 to 19) per cent; PNI = 0·31). Early catheter removal was superior for UTI (RD -11 (95 per cent c.i. -17 to -4) per cent; P = 0·001). Results for length of stay were mixed. There were insufficient data to conduct subgroup analyses. CONCLUSION: The existing literature is inconclusive for non-inferiority of early versus late urinary catheter removal for acute urinary retention. Early catheter removal is superior in terms of reducing the risk of UTI.

ANTECEDENTES: Las sondas urinarias se colocan después de la cirugía rectal para prevenir la retención urinaria, pero su uso prolongado puede aumentar el riesgo de infección del tracto urinario. Esta revisión evaluó si la retirada precoz de la sonda urinaria no fue inferior a la retirada tardía del catéter en cuanto al riesgo de retención urinaria aguda tras cirugía rectal. MÉTODOS: Se realizaron búsquedas en las bases de datos MEDLINE, Embase y en el Registro Central Cochrane de Ensayos Controlados desde enero de 1980 hasta febrero de 2019. Se consideraron elegibles los ensayos controlados aleatorizados que comparaban la retirada precoz y tardía de la sonda tras cirugía rectal. Las variables principales fueron la retención urinaria aguda y la infección del tracto urinario. La variable secundaria fue la duración de la estancia hospitalaria. Se consideró retirada precoz cuando ésta ocurrió hasta el segundo día postoperatorio mientras que más allá de ese tiempo se consideró retirada tardía. El margen de no inferioridad de uno de los ensayos incluidos se utilizó para el análisis de la retención urinaria (ΔNI = 15%). Las estimaciones agrupadas de las diferencias de riesgo se derivaron de los modelos de efectos aleatorios. El riesgo de sesgo se evaluó utilizando una herramienta de riesgo de sesgo Cochrane modificada. RESULTADOS: Se incluyeron cuatro ensayos que incluyeron un total de 409 pacientes. No se encontraron evidencias suficientes para concluir la no inferioridad de la retirada precoz del catéter versus la retirada tardía para la retención urinaria aguda (diferencia de riesgo, risk difference, RD 9%, i.c. del 90% -1% a 19%, valor de la P para no inferioridad, P value for non-inferiority, PNI = 0,31). La retirada precoz del catéter fue superior con relación a la infección del tracto urinario (RD -11%, IC del 95%: -17% a -4%, P = 0,001). Los resultados de la duración de la estancia hospitalaria fueron mixtos. No hubo datos suficientes para realizar análisis de subgrupos. CONCLUSIÓN: La literatura existente no es concluyente para determinar la no inferioridad de la retirada precoz de la sonda urinaria versus la retirada tardía con relación a la retención urinaria aguda. La retirada precoz de la sonda es superior y reduce el riesgo de infección del tracto urinario.

Immediate and long-term impact of the COVID-19 pandemic on delivery of surgical services.

BACKGROUND: The ongoing pandemic is having a collateral health effect on delivery of surgical care to millions of patients. Very little is known about pandemic management and effects on other services, including delivery of surgery. METHODS: This was a scoping review of all available literature pertaining to COVID-19 and surgery, using electronic databases, society websites, webinars and preprint repositories. RESULTS: Several perioperative guidelines have been issued within a short time. Many suggestions are contradictory and based on anecdotal data at best. As regions with the highest volume of operations per capita are being hit, an unprecedented number of operations are being cancelled or deferred. No major stakeholder seems to have considered how a pandemic deprives patients with a surgical condition of resources, with patients disproportionally affected owing to the nature of treatment (use of anaesthesia, operating rooms, protective equipment, physical invasion and need for perioperative care). No recommendations exist regarding how to reopen surgical delivery. The postpandemic evaluation and future planning should involve surgical services as an essential part to maintain appropriate surgical care for the population during an outbreak. Surgical delivery, owing to its cross-cutting nature and synergistic effects on health systems at large, needs to be built into the WHO agenda for national health planning. CONCLUSION: Patients are being deprived of surgical access, with uncertain loss of function and risk of adverse prognosis as a collateral effect of the pandemic. Surgical services need a contingency plan for maintaining surgical care in an ongoing or postpandemic phase.

ANTECEDENTES: La pandemia en curso tiene un efecto colateral sobre la salud en la prestación de atención quirúrgica a millones de pacientes. Se sabe muy poco sobre el manejo de la pandemia y sus efectos colaterales en otros servicios, incluida la prestación de servicios quirúrgicos. MÉTODOS: Se ha realizado una revisión de alcance de toda la literatura disponible relacionada con COVID-19 y cirugía utilizando bases de datos electrónicas, páginas web de sociedades, seminarios online y repositorios de pre-publicaciones. RESULTADOS: Se han publicado varias guías perioperatorias en un corto período de tiempo. Muchas recomendaciones son contradictorias y, en el mejor de los casos, se basan en datos anecdóticos. A medida que las regiones con el mayor volumen de operaciones per cápita se ven afectadas, se cancela o difiere un número sin precedentes de operaciones. Ninguna de las principales partes interesadas parece haber considerado cómo una pandemia priva de recursos a los pacientes que necesitan una intervención quirúrgica, con pacientes afectados de manera desproporcionada debido a la naturaleza del tratamiento (uso de anestesia, quirófanos, equipo de protección, contacto físico y necesidad de atención perioperatoria). No existen recomendaciones sobre cómo reanudar la actividad quirúrgica. La evaluación tras la pandemia y la planificación futura deben incluir a los servicios quirúrgicos como una parte esencial para mantener la atención quirúrgica adecuada para la población también durante un brote epidémico. La prestación de servicios quirúrgicos, debido a su naturaleza transversal y a sus efectos sinérgicos en los sistemas de salud en general, debe incorporarse a la agenda de la OMS para la planificación nacional de la salud. CONCLUSIÓN: Los pacientes se ven privados de acceso a la cirugía con una pérdida de función incierta y riesgo de un pronóstico adverso como efecto colateral de la pandemia. Los servicios quirúrgicos necesitan un plan de contingencia para mantener la atención quirúrgica durante la pandemia y en la fase post-pandemia.

Multidisciplinary care of breast cancer patients: a scoping review of multidisciplinary styles, processes, and outcomes.

Background: Clinical practice guidelines recommend a multidisciplinary approach to cancer care that brings together all relevant disciplines to discuss optimal disease management. However, the literature is characterized by heterogeneous definitions and few reviews about the processes and outcomes of multidisciplinary care. The objective of this scoping review was to identify and classify the definitions and characteristics of multidisciplinary care, as well as outcomes and interventions for patients with breast cancer. Methods: A systematic search for quantitative and qualitative studies about multidisciplinary care for patients with breast cancer was conducted for January 2001 to December 2017 in the following electronic databases: medline, embase, PsycInfo, and cinahl. Two reviewers independently applied our eligibility criteria at level 1 (title/abstract) and level 2 (full-text) screening. Data were extracted and synthesized descriptively. Results: The search yielded 9537 unique results, of which 191 were included in the final analysis. Two main types of multidisciplinary care were identified: conferences and clinics. Most studies focused on outcomes of multidisciplinary care that could be variously grouped at the patient, provider, and system levels. Research into processes tended to focus on processes that facilitate implementation: team-working, meeting logistics, infrastructure, quality audit, and barriers and facilitators. Summary: Approaches to multidisciplinary care using conferences and clinics are well described. However, studies vary by design, clinical context, patient population, and study outcome. The heterogeneity of the literature, including the patient populations studied, warrants further specification of multidisciplinary care practice and systematic reviews of the processes or contexts that make the implementation and operation of multidisciplinary care effective.

Establishing funding rates for colonoscopy and gastroscopy procedures in Ontario.

Introduction: This paper describes the funding rates established in Ontario to reflect best practices in hospital-based care delivery for these endoscopic procedures: colonoscopy, colonoscopy biopsy, gastroscopy, gastroscopy biopsy, and colonoscopy combined with gastroscopy. Methods: The funding rates are based on direct costs and were established using a micro-costing approach after receipt of inputs from 3 working groups and a review of the administrative data and literature, where applicable. The first group advised on nursing activities, time, and staffing ratios along the patient pathway for each of the procedures. The second group provided recommendations about the duration for each procedure, and the third group provided information about supplies and equipment, their use, and costs. Results: The resulting funding rates are $161.18 for colonoscopy and $151.08 for gastroscopy (without accompanying interventions), $16.06 for colonoscopy biopsy and $8.22 for gastroscopy biopsy (added to the respective procedures), and $207.26 for combined colonoscopy and gastroscopy. Detailed costs for each component embedded in the rates are also provided. Conclusions: The rates came into effect in April 2018. The process and outcomes described here allowed for a transparent pricing mechanism in which funding follows the patient, clinical expert consensus is the basis for practice, and providers and payers both understand the components.

Taking the pulse of multidisciplinary cancer conferences for breast cancer care in Canada: A stocktake of current practice.

AIM: International guidelines highlight the importance of implementation supports and quality monitoring of multidisciplinary care for breast cancer. In Canada, Ontario has standards for formal multidisciplinary cancer conferences (MCCs), but other provinces/territories do not. This study aimed to stocktake MCCs for breast cancer in Canadian sites participating in the RUBY cohort study (Reducing the Burden of Breast Cancer in Young Women) to better understand variations in multidisciplinary care across Canada and to add to the international literature. METHODS: A cross-sectional survey was conducted with surgeons and surgical oncologists representing 34 clinical centres participating in RUBY. Questions were grouped according to: type of multidisciplinary care, implementation, function, practice, participation and presentation, operation, and demographics, and included a mix of Likert-based, tick box and open-ended questions. RESULTS: Twenty-two responses (65%) were received. 91% of respondents reported that formal MCCs are part of regular practice. However, variation exists in the supports in place for ongoing implementation of MCCs, the understanding of the functions of MCCs, and the patients presented for discussion. Results also suggest less formalized processes for MCC in provinces without practice standards. CONCLUSIONS: Response differences between Ontario and elsewhere suggest that standards for MCC and supports for their implementation make a positive difference in their operation. However, ongoing operational challenges and issues with attendance exist for all sites and suggest that along with development of practice standards, incentives for participation and further education on benefits and function of MCC may support uptake of MCCs in clinical practice.

Reoperation for inguinal hernia recurrence in Ontario: a population-based study.

PURPOSE: Despite the frequency with which inguinal hernia repairs (IHR) are performed, the real-world comparative effectiveness of laparoscopic versus open repairs is not well established. We compared the rate of recurrent inguinal hernia after laparoscopic and open mesh procedures. METHODS: We designed a population-based retrospective cohort study using linked administrative databases including adult patients in Ontario, Canada, who underwent primary IHR from April 1, 2003 to December 31, 2012. Patients were followed to August 31, 2014. Our primary outcome was reoperation for recurrent IHR, with covariate adjustment using Cox proportional hazards modeling. We constructed separate models to evaluate the effect of surgeon caseload on recurrence rates. RESULTS: We identified 93,501 adults undergoing primary IHR (85.4% open with mesh and 14.6% laparoscopic) with a median follow-up of 5.5 years. The 5-year cumulative risk of recurrent IHR was 2.0% in the open group and 3.4% in the laparoscopic group. After adjusting for patient and surgeon factors, we found that patients who underwent laparoscopic repair had a higher risk of recurrent IHR than those who underwent open repair when annual surgeon volume in the preceding year was ≤25 technique-specific cases (HR 1.76; 95% CI 1.45-2.13) or 26-50 technique-specific cases (HR 1.78; 95% CI 1.08-2.93). Few high-volume laparoscopic surgeons (> 50 cases/year) could be identified. Laparoscopic IHR did not carry a higher risk of recurrence for patients whose surgeons had performed > 50 technique-specific cases in the preceding year (HR 1.21; 95% CI 0.45-3.26). CONCLUSION: Laparoscopic IHR is generally associated with a higher risk of recurrence than open IHR. Though high-volume surgeons may be able to achieve equivalent results with laparoscopic and open techniques, few surgeons in our study population met this volume criterion for laparoscopic repairs.