Safety and utility of panniculectomy in renal transplant candidates and end stage renal disease patients

BACKGROUND

As the obesity crisis in the United States continues, some renal transplantation centers have liberalized their BMI criteria necessary for transplant eligibility. More individuals with larger body-habitus related comorbidities with End-Stage Renal Disease (ESRD) now qualify for renal transplantation (RT). Surgical modalities from other fields also interact with this patient population.

METHODS

In order to assess surgical outcomes of panniculectomy in the context of renal transplantation and ESRD, the authors performed a systematic review following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) 2020 guidelines. Due to a paucity of existing primary studies, we retrospectively collected data on patients with ESRD undergoing panniculectomy from the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) to evaluate outcomes of body contouring in this patient population.

RESULTS

From the systematic review, a total of 783 ESRD patients underwent panniculectomy among the studies identified. Of these, 91 patients underwent panniculectomy simultaneously to RT while 692 had their pannus resected prior to kidney transplant. The most common complication was hematoma followed by wound dehiscence. From the NSQIP database, 24 868 patients met the inclusion criteria for analysis. In the setting of renal transplant status, patients with diabetes, hypertension requiring medication, and requiring dialysis were more likely to suffer postoperative complications (OR 1.31, 1.15, and 2.2, respectively). However, upon sub-analysis of specific types of complications, the only retained association was between diabetes and wound complication.

CONCLUSION

Preliminary data show that panniculectomy in ESRD patients appears to be safe, though with a nominal increased risk for complications. Pannus resection does not appear to impact post-transplantation outcomes, including long-term allograft survival. Larger, higher powered, randomized studies are needed to confirm the safety, utility, and medical benefit of panniculectomy in the context of renal transplantation.

The Impact of Body Mass Index on Adverse Outcomes Associated with Panniculectomy: A Multimodal Analysis

BACKGROUND

Overhanging pannus may be detrimental to ambulation, urination, sexual function, and social well-being. Massive weight loss patients often have high residual body mass index (BMI) and comorbidities presenting a unique challenge in panniculectomy patient selection. This study aims to better characterize the role of BMI in post-operative complications following panniculectomy.

METHODS

A meta-analysis attempted to assess the impact of BMI on complications following panniculectomy. Cochrane Q and I 2 test statistics measured study heterogeneity, with subsequent random effects meta-regression investigating these results. After this, all panniculectomy patients in the National Surgical Quality Improvement Program (NSQIP) years 2007-2019, were analyzed. Univariate and multivariable tests assessed the relative role of BMI on 30-day postoperative complications.

RESULTS

Thirty-four studies satisfied inclusion criteria, revealing very high heterogeneity (Cochrane Q = 2453.3; I 2 = 99.1%), precluding further meta-analysis results. Receiver operator curves demonstrated BMI was a significant predictor of both all causes (area under the curve (AUC): 0.64, 95%CI:0.62-0.66) and wound complications (AUC:0.66, 95%CI:0.63-0.69). BMI remained significant following multivariable regression analyses. Restricted cubic spines demonstrated marginal increases in complication incidence above 33.2 and 35 for all-cause and wound complications respectively.

CONCLUSION

Reported literature regarding postoperative complications in panniculectomy patients is highly heterogeneous, and may limit evidence-based care. Complication incidence positively correlated with BMI, though ROC demonstrated its limitations as the sole predictive variable. Further, RSC demonstrated diminishing marginal predictive capacity of BMI for incremental increases in BMIs above 33.2-35 kg/m 2. These findings support a re-evaluation of the role of BMI cut-offs in panniculectomy patient selection.

Graft Survival and Acute Rejection in Cross-Sex Solid Organ Transplants: A Systematic Review and Meta-Analysis to Inform Vascularized Composite Allotransplantation Practice

BACKGROUND

Out of nearly 90 hand and 50 face transplant recipients, only 5 have received a cross-sex vascularized composite allotransplantation (CS-VCA) to date. CS-VCA has the potential to expand the donor pool and has been shown to be anatomically feasible and ethically acceptable in previous cadaveric and survey studies. However, there is a lack of immunologic data. This study aims to evaluate the immunologic feasibility of CS-VCA through analysis of the solid organ transplant (SOT) literature, given the paucity of CS-VCA data. We hypothesize the rates of acute rejection (AR) and graft survival (GS) in CS vs. same-sex (SS)-SOT to be similar.

METHODS

A systematic review and meta-analysis of the PubMed, EMBASE, and Cochrane databases were performed in accordance with PRISMA guidelines. Studies comparing GS or AR episodes in CS- and SS- adult kidney (KT) and liver transplant (LT) populations were included. Odds ratios were calculated for overall GS and AR for all SS and CS transplant combinations (male-to-female (MTF), female-to-male (FTM) and overall).

RESULTS

A total of 693 articles were initially identified and 25 studies were included in the meta-analysis. No significant difference in GS was noted between SS-KT vs. CS-KT (OR 1.04 [1.00, 1.07]; P=0.07), SS-KT vs. MTF-KT (OR 0.97 [0.90, 1.04]; P=0.41) and SS-LT vs. MTF-LT (OR 0.95 [0.91, 1.00]; P=0.05). No significant difference in AR was noted between SS-KT vs. MTF-KT (OR 0.99 [0.96, 1.02]; P=0.57), SS-LT vs. CS-LT (OR 0.78 [0.53, 1.16]; P=0.22) and SS-LT vs. FTM-LT (OR 1.03 [0.95, 1.12]; P=0.47). For the remaining pairings, GS was significantly increased and AR was significantly decreased in the SS transplants.

CONCLUSIONS

Published data suggest immunologic feasibility of CS-KT and CS-LT, with the potential for generalization to the VCA population. In theory, CS-VCA could expand the potential donor pool, leading to decreased wait times for recipients.

Microwave ablation for hepatic malignancies: a systematic review of the technology and differences in devices

BACKGROUND

Microwave ablation (MWA) has become the standard thermal-based treatment for hepatic malignancies in patients who have unresectable disease based on the biology of the tumor, the patients' comorbidities, and certain disease sites. The technical effectiveness, ablation success, local recurrence rates of hepatic malignancies treated with the various commercial microwave ablation devices has not been previously published in the peer reviewed literature. The aim of this systematic review is to summarize the clinical outcomes for the various MWA devices in the use of a hepatic malignancies to best educate hepatic surgeons as well as interventional radiologists.

METHODS

A comprehensive review of the literature and instructions for use of each device that was published from 1/2013 to 12/2020 was performed. The main outcomes extracted were technical success, ablation success, major complications, local and new recurrence rates, recurrence-free survival, ablation volumes, time, and the number of antennas required. A qualitative review of the literature was performed.

RESULTS

In total, 29 studies reporting data on 3250 patients and 4500 tumors were included in this review. Median patient age was 60.5 years (range 3-91). 76.3% (2420 M/753 F) of patients were male. Hepatocellular carcinoma (55%) was the most common tumor pathology followed by colorectal liver metastasis (10%) and cholangiocarcinoma (4%). A majority of studies reported technical success (range, 91.6-100%) and ablation success (range, 73.1-100%), as well as major complications (range, 0-9.1%). Local recurrence (range, 0-50%) was reported by 21 of the studies; however, new recurrence (range, 12.2-64%) was reported less frequently (6 studies) and were further specified in 12, six, and four studies as intrahepatic distant recurrence (11.3-54.2%), extrahepatic distant recurrence (3.6-20%), and metastasis (1.1-36%). A total of three, six, and five studies report disease, progression, and recurrence-free survival rates, respectively.

CONCLUSION

Microwave ablation is frequently used for the treatment of hepatic malignancies. A thorough understanding of the clinical outcomes associated with different pathologies and MWA devices can improve surgeon awareness and help prepare for operative planning and patient management. More consistent reporting of key outcomes in the literature is needed to achieve such an understanding.

Geographic Trends of International Medical Graduate Residents and Faculty in US Plastic Surgery Training Programs

BACKGROUND

Of the academic plastic surgeons in the United States, 13.6% are international medical graduates (IMGs). The objective of this study was to identify the countries from which IMGs obtained their medical degrees and the states they matched in. We sought to establish a correlation between IMG faculty and residents in plastic surgery programs.

METHODS

Plastic surgery program Web sites were reviewed. The primary outcome of interest was the country IMG residents had obtained their medical degrees from. Secondary outcomes of interest were program state location, IMG resident postgraduate year, and programs' number of IMG faculty.

RESULTS

One hundred one programs were screened. A total of 39 states were represented; there were 1262 current residents, of which 92 (7.3%) were IMGs. International medical graduate residents received their medical degrees from 46 different countries. The most common countries were England (n = 6 [6.5%]) for IMG residents and Canada (24.5%) for IMG faculty. The most common region represented for residents was South America (n = 44 [47.8%]). The highest proportions of IMGs per total state plastic surgery residents were found in West Virginia (33.3%) and Minnesota (25%); 13.5% and 15.6% of program directors and program chairs were IMGs, respectively. There was a statistically significant difference between the proportion of IMG residents in programs that had an IMG program director versus programs with no IMG program director (P = 0.016). No such statistically significant difference was found between the proportion of IMG residents in given programs with IMG chairs (P = 0.55). There were significantly more IMG faculty in programs with IMG chairs (P = 0.001). The number of IMG faculty was positively correlated to the number of IMG residents in a given program (P = 0.0001, r = 0.39).

CONCLUSION

International medical graduate residents constitute a small but appreciable portion of current plastic surgery residents; the majority have earned their degrees from the South America region. International medical graduate plastic surgery residents are more likely to be recruited to programs that have an IMG program director and a higher number of IMG faculty. International medical graduate faculty have a strong representation in academic plastic surgery, as evidenced by the percentage of IMG program directors and chairs. Programs with IMG chairs had a greater number of IMG faculty.

Patient-centred outcomes and dental implant placement in computer-aided free flap mandibular reconstruction: a systematic review and meta-analysis

Computerised surgical planning (CSP) and computer-aided design and manufacturing (CAD/CAM) have been demonstrated to increase surgical accuracy and reduce operative time in free flap mandibular reconstruction, but evidence is lacking as to their impact on patient-centred outcomes. Implant-supported dental prostheses, however, have been associated with improved quality of life outcomes following free flap mandibular reconstruction. We aim to review reported patient-centred outcomes in mandibular reconstruction with CSP and CAD/CAM and determine whether use of these technologies is associated with higher rates of dental implant placement following free flap mandibular reconstruction. On December 20, 2020, a systematic review and meta-analysis were conducted according to PRISMA guidelines for studies reporting quality of life, functional outcomes, and rates of dental implant placement in computer-aided free flap mandibular reconstruction. A random-effects meta-analysis was performed to compare dental implant placement rates between surgeries using CSP and those using conventional freehand techniques. A total of 767 articles were screened. Nine articles reporting patient-centred outcomes and 16 articles reporting dental implant outcomes were reviewed. Of those reporting dental implant outcomes, five articles, representing a total of 302 cases, were included in the meta-analysis. Use of CSP was associated with a significant increase in the likelihood of dental implant placement, with an odds ratio of 2.70 (95% CI 1.52 to 4.79, p = 0.0007). Standardised reporting methods and controlled studies are needed to further investigate the impact of CSP and CAD/CAM technologies on functional outcomes and patient-reported quality of life in free flap mandibular reconstruction. Use of CSP and CAD/CAM technologies is associated with higher rates of dental implant placement in patients undergoing free flap mandibular reconstruction when compared to conventional freehand techniques.

Complete Penile Amputation: An Anatomical Reference and Surgical Pearls to Ensure a Successful Replantation

How common are penile amputations, and how are they treated?What key anatomic structures are involved?What are some technical pearls for a successful replantation?What are common complications, and how can they be prevented/treated?

Restoring Breast Volume in High BMI Patients: A Single-Center Review of Breast Reconstruction Using Hyperinflated Saline Implants

BACKGROUND

Breast reconstruction in the obese patient is often fraught with poor patient satisfaction due to inadequate volume restoration. The off-label hyperinflation of saline implants is a direct yet controversial solution to this problem, with limited studies in the literature. This study sought to determine the safety and efficacy of this technique for breast reconstruction.

METHODS

A retrospective chart review was performed to identify all patients with a body mass index (BMI) greater than or equal to 30 kg/m2 who underwent breast reconstruction between the years 2013 to 2020 with saline implants filled beyond the manufacturer's maximum recommended volume.

RESULTS

The 21 patients identified had an average age of 49 years. The mean BMI was 39.5 kg/m2. A total of 42 implants were placed; 34 were 800 mL, 4 were 750 mL, and 4 were 700 mL. The average overfill volume was 302 mL (138%). Mean follow-up was 65.0 months. Of these, 1 (4.8%) patient with a history of chest wall radiotherapy underwent reoperation for unilateral implant exposure 27 days after the index procedure, no patient sustained spontaneous leak or rupture, and 1 patient had unilateral deflation following emergent central line and pacemaker placement 2 years after the implant was placed for an unrelated cardiovascular event.

CONCLUSIONS

Hyperinflation of saline implants beyond the maximum recommended volume may be considered for volume replacement in obese patients undergoing implant-based breast reconstruction. This practice is well tolerated, has a complication rate comparable to using implants filled to the recommended volume, and has the potential to restore lost breast volume in the obese patient post mastectomy.

Treatment of Osteochondral Fractures After Acute Patellofemoral Instability: A Critical Analysis Review

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An osteochondral fracture (OCF) of the patella or the femur is a frequent sequela after an episode of acute patellofemoral instability.

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Patients commonly present with anterior knee pain after direct trauma to the patella or a noncontact twisting injury.

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Radiographs and magnetic resonance imaging (MRI) are the most common imaging modalities that are used to diagnose OCFs.

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Arthroscopy may be indicated in cases of displaced OCFs, and the decision regarding osteochondral fragment fixation or loose body removal depends on fragment size, location, and extent of injury.

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Most of the current literature suggests worse outcomes for patients with OCFs who undergo nonoperative treatment, no significant differences in outcomes for patients sustaining an acute patellar dislocation with or without an OCF, and inconclusive results concerning outcomes for patients treated with loose body removal compared with fixation.

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Current outcome data are limited by studies with low levels of evidence; therefore, well-designed randomized controlled trials are needed.

Mapping conflict of interests: scoping review

OBJECTIVE

To identify all known ties between the medical product industry and the healthcare ecosystem.

DESIGN

Scoping review.

METHODS

From initial literature searches and expert input, a map was created to show the network of medical product industry ties across parties and activities in the healthcare ecosystem. Through a scoping review, the ties were then verified, cataloged, and characterized, with data abstracted on types of industry ties (financial, non-financial), applicable policies for conflict of interests, and publicly available data sources.

MAIN OUTCOME MEASURES

Presence and types of medical product industry ties to activities and parties, presence of policies for conflict of interests, and publicly available data.

RESULTS

A map derived through synthesis of 538 articles from 37 countries shows an extensive network of medical product industry ties to activities and parties in the healthcare ecosystem. Key activities include research, healthcare education, guideline development, formulary selection, and clinical care. Parties include non-profit entities, the healthcare profession, the market supply chain, and government. The medical product industry has direct ties to all parties and some activities through multiple pathways; direct ties extend through interrelationships among parties and activities. The most frequently identified parties were within the healthcare profession, with individual professionals described in 422 (78%) of the included studies. More than half (303, 56%) of the publications documented medical product industry ties to research, with clinical care (156, 29%), health professional education (145, 27%), guideline development (33, 6%), and formulary selection (8, 1%) appearing less often. Policies for conflict of interests exist for some financial and a few non-financial ties; publicly available data sources seldom describe or quantify these ties.

CONCLUSIONS

An extensive network of medical product industry ties to activities and parties exists in the healthcare ecosystem. Policies for conflict of interests and publicly available data are lacking, suggesting that enhanced oversight and transparency are needed to protect patient care from commercial influence and to ensure public trust.

Impact of Provider Imaging Practices on Survival Outcomes in Advanced Ovarian Cancer

BACKGROUND

This study sought to describe how high- versus low-frequency surveillance imaging practices among providers at Memorial Sloan Kettering Cancer Center (MSKCC) impact overall survival (OS) and time to recurrence of patients with advanced epithelial ovarian cancer in first remission.

METHODS

The study cohort included patients with stage II-IV high-grade epithelial ovarian cancer diagnosed in January 2001 through January 2017 who experienced recurrence after initial platinum-based chemotherapy. To determine usual imaging practices for providers at MSKCC, median frequency of CT or MRI of the abdomen/pelvis was calculated among patients with a long-term remission (defined as at least 1 year) treated by each provider. Cox proportional hazards models were used to examine differences in OS and time to recurrence among patients treated by providers with high versus low imaging frequency practices, with additional subgroup analysis among patients with elevated CA-125 levels >35 U/mL at diagnosis. Chi-square tests were used to examine differences in the proportion of patients who enrolled in clinical trials or underwent secondary cytoreductive surgery (SCS) by imaging frequency.

RESULTS

A total of 543 patients were treated by providers with high imaging frequency (>1 scan every 12 months) and 141 were treated by providers with low imaging frequency (≤1 scan every 12 months). Time to recurrence was shorter among patients treated by providers with high versus low imaging frequency (18.0 vs 19.2 months; hazard ratio, 1.33; P=.003). Results were similar when restricted to patients with elevated CA-125 levels at diagnosis. There was no significant difference in OS, clinical trial enrollment, or SCS by imaging practice.

CONCLUSIONS

Within the limitations of this retrospective analysis, patients with advanced ovarian cancer treated by high-frequency-imaging providers had earlier detection of recurrence. Future analyses in a larger population are warranted to elucidate the risks versus benefits of surveillance imaging.

Risk Factors for Failure After Anterior Cruciate Ligament Reconstruction in a Pediatric Population: A Prediction Algorithm

Background:

Anterior cruciate ligament reconstruction (ACLR) in pediatric patients is becoming increasingly common. There is growing yet limited literature on the risk factors for revision in this demographic.

Purpose:

To (1) determine the rate of pediatric revision ACLR in a nationally representative sample, (2) ascertain the associated patient- and injury-specific risk factors for revision ACLR, and (3) examine the differences in the rate and risks of revision ACLR between pediatric and adult patients.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

The PearlDiver patient record database was used to identify adult patients (age ≥20 years) and pediatric patients (age <20 years) who underwent primary ACLR between 2010 and 2015. At 5 years postoperatively, the risk of revision ACLR was compared between the adult and pediatric groups. ACLR to the contralateral side was also compared. Multivariate logistic regression was used to determine the significant risk factors for revision ACLR and the overall reoperation rates in pediatric and adult patients; from these risk factors, an algorithm was developed to predict the risk of revision ACLR in pediatric patients.

Results:

Included were 2055 pediatric patients, 1778 adult patients aged 20 to 29 years, and 1646 adult patients aged 30 to 39 years who underwent ACLR. At 5 years postoperatively, pediatric patients faced a higher risk of revision surgery when compared with adults (18.0 % vs 9.2% [adults 20-29 years] and 7.1% [adults 30-39 years]; P < .0001), with significantly decreased survivorship of the index ACLR (P < .0001; log-rank test). Pediatric patients were also at higher risk of undergoing contralateral ACLR as compared with adults (5.8% vs 1.6% [adults 20-29 years] and 1.9% [adults 30-39 years]; P < .0001). Among the pediatric cohort, boys (odds ratio [OR], 0.78; 95% CI, 0.63-0.96; P = .0204) and patients >14 years old (OR, 0.62; 95% CI, 0.45-0.86; P = .0035) had a decreased risk of overall reoperation; patients undergoing concurrent meniscal repair (OR, 1.84; 95% CI, 1.43-2.38; P < .0001) or meniscectomy (OR, 2.20; 95% CI, 1.72-2.82; P < .0001) had an increased risk of revision surgery. According to the risk algorithm, the highest probability for revision ACLR was in girls <15 years old with concomitant meniscal and medial collateral ligament injury (36% risk of revision).

Conclusion:

As compared with adults, pediatric patients had an increased likelihood of revision ACLR, contralateral ACLR, and meniscal reoperation within 5 years of an index ACLR. Families of pediatric patients—especially female patients, younger patients, and those with concomitant medial collateral ligament and meniscal injuries—should be counseled on such risks.

Failure Rates of Autograft and Allograft ACL Reconstruction in Patients 19 Years of Age and Younger: A Systematic Review and Meta-Analysis

BACKGROUND

Graft choice for pediatric anterior cruciate ligament reconstruction (ACLR) is determined by several factors. There is limited information on the use and outcomes of allograft ACLR in pediatric patients. The purpose of this systematic review and meta-analysis was to quantify reported failure rates of allograft versus autograft ACLR in patients ≤19 years of age with ≥2 years of follow-up. We hypothesized that there would be higher rates of failure for allograft compared with autograft ACLR in this population.

METHODS

PubMed/MEDLINE and Embase databases were systematically searched for literature regarding allograft and autograft ACLR in pediatric/adolescent patients. Articles were included if they described a cohort of patients with average age of ≤19 years, had a minimum of 2 years of follow-up, described graft failure as an outcome, and had a Level of Evidence grade of I to III. Qualitative review and quantitative meta-analysis were performed to compare graft failure rates. A random-effects model was created to compare failure events in patients receiving allograft versus autograft in a pairwise fashion. Data analysis was completed using RevMan 5.3 software (The Cochrane Collaboration).

RESULTS

The database search identified 1,604 studies; 203 full-text articles were assessed for eligibility. Fourteen studies met the inclusion criteria for qualitative review; 5 studies were included for quantitative meta-analysis. Bone-patellar tendon-bone (BTB) represented 58.2% (n = 1,012) of the autografts, and hamstring grafts represented 41.8% (n = 727). Hybrid allografts (autograft + supplemental allograft) represented 12.8% (n = 18) of all allograft ACLRs (n = 141). The unweighted, pooled failure rate for each graft type was 8.5% for BTB, 16.6% for hamstring, and 25.5% for allograft. Allografts were significantly more likely than autografts to result in graft failure (odds ratio, 3.87; 95% confidence interval, 2.24 to 6.69).

CONCLUSIONS

Allograft ACLR in pediatric and adolescent patients should be used judiciously, as existing studies revealed a significantly higher failure rate for allograft compared with autograft ACLR in this patient population. Additional studies are needed to improve the understanding of variables associated with the high ACLR failure rate among pediatric and adolescent patients.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Association Between Marijuana Use and Risk of Cancer: A Systematic Review and Meta-analysis

Importance

Marijuana use is common and growing in the United States amid a trend toward legalization. Exposure to tobacco smoke is a well-described preventable cause of many cancers; the association of marijuana use with the development of cancer is not clear.

Objective

To assess the association of marijuana use with cancer development.

Data Sources

A search of PubMed, Embase, PsycINFO, MEDLINE, and the Cochrane Library was conducted on June 11, 2018, and updated on April 30, 2019. A systematic review and meta-analysis of studies published from January 1, 1973, to April 30, 2019, and references of included studies were performed, with data analyzed from January 2 through October 4, 2019.

Study Selection

English-language studies involving adult marijuana users and reporting cancer development. The search strategy contained the following 2 concepts linked together with the AND operator: marijuana OR marihuana OR tetrahydrocannabinol OR cannabinoid OR cannabis; AND cancer OR malignancy OR carcinoma OR tumor OR neoplasm.

Data Extraction and Synthesis

Two reviewers independently reviewed titles, abstracts, and full-text articles; 3 reviewers independently assessed study characteristics and graded evidence strength by consensus.

Main Outcomes and Measures

Rates of cancer in marijuana users, with ever use defined as at least 1 joint-year exposure (equivalent to 1 joint per day for 1 year), compared with nonusers. Meta-analysis was conducted if there were at least 2 studies of the same design addressing the same cancer without high risk of bias when heterogeneity was low to moderate for the following 4 cancers: lung, head and neck squamous cell carcinoma, oral squamous cell carcinoma, and testicular germ cell tumor (TGCT), with comparisons expressed as odds ratios (ORs) with 95% CIs.

Results

Twenty-five English-language studies (19 case-control, 5 cohort, and 1 cross-sectional) were included; few studies (n = 2) were at low risk of bias. In pooled analysis of case-control studies, ever use of marijuana was not associated with head and neck squamous cell carcinoma or oral cancer. In pooled analysis of 3 case-control studies, more than 10 years of marijuana use (joint-years not reported) was associated with TGCT (OR, 1.36; 95% CI, 1.03-1.81; P = .03; I2 = 0%) and nonseminoma TGCT (OR, 1.85; 95% CI, 1.10-3.11; P = .04; I2 = 0%). Evaluations of ever use generally found no association with cancers, but exposure levels were low and poorly defined. Findings for lung cancer were mixed, confounded by few marijuana-only smokers, poor exposure assessment, and inadequate adjustment; meta-analysis was not performed for several outcomes.

Conclusions and Relevance

Low-strength evidence suggests that smoking marijuana is associated with developing TGCT; its association with other cancers and the consequences of higher levels of use are unclear. Long-term studies in marijuana-only smokers would improve understanding of marijuana's association with lung, oral, and other cancers.

Trial Registration

PROSPERO identifier: CRD42018102457.

Development of a Conceptual Map of Negative Consequences for Patients of Overuse of Medical Tests and Treatments

IMPORTANCE

Overuse of medical tests and treatments is an increasingly recognized problem across health systems; best practices for reducing overuse are not clear. Framing the problem in terms of the spectrum of potential patient harm is likely to be an effective strategy for clinician and patient engagement in efforts to reduce overuse, but the scope of negative consequences of overuse for patients has not been well described.

OBSERVATIONS

We sought to generate a comprehensive conceptual map documenting the processes through which overused tests and treatments lead to multiple domains of negative consequences for patients. For map development, an iterative consensus process was informed by structured review of the literature on overuse using PubMed and input from a panel of 6 international experts. For map verification, a systematic review was performed of case reports involving overused services, identified through literature review and manual review of relevant article collections. The conceptual map documents that overused tests and treatments and resultant downstream services generate 6 domains of negative consequences for patients: physical, psychological, social, financial, treatment burden, and dissatisfaction with health care. Negative consequences can result from overused services and from downstream services; they can also trigger further downstream services that in turn can lead to more negative consequences, in an ongoing feedback loop. Case reports on overuse confirmed the processes and domains of the conceptual map. Cases also revealed strengths and weaknesses in published communication about overuse: they were dominated by physical harms, with other negative consequences receiving far less attention.

CONCLUSIONS AND RELEVANCE

This evidence-based conceptual map clarifies the processes by which overused tests and treatments result in negative consequences for patients; it also documents multiple domains of negative consequences experienced by patients. The map will be useful for facilitating comprehensive communication about overuse, estimating harms and costs associated with overused services, and informing health system efforts to reduce overuse.

UKPDS 21: low prevalence of the mitochondrial transfer RNA gene (tRNA(Leu(UUR))) mutation at position 3243bp in UK Caucasian type 2 diabetic patients

Some patients with Type 2 (non-insulin-dependent) diabetes mellitus possess a mitochondrial mutation in the tRNA(Leu(UUR)) gene at position 3243 bp. These subjects show a maternal mode of inheritance and often have hearing defects. In French and Japanese populations, this mutation may be present in 1-3% of subjects with a family history of diabetes. We assessed the prevalence of this mutation in newly diagnosed diabetic subjects in the UK white Caucasian population. The 3243 bp mutation was not detected in 500 randomly selected Type 2 diabetic subjects, 50 gestational diabetic subjects, and members of a MODY pedigree. Two of 748 (0.27%) Type 2 diabetic subjects with a family history of diabetes were found to possess the mutation. These subjects had an early age of diagnosis (M 38 years; F 36 years) and were non-obese. The male patient showed evidence of markedly impaired beta-cell function and deafness, while the female was not deaf, had approximately 50% of normal pancreatic function and responded well to diet. The mutation in the tRNA(Leu(UUR)) gene probably occurs in only approximately 0.1-0.2% of white Caucasian Type 2 diabetic patients in the UK.

High prevalence of a missense mutation of the glucokinase gene in gestational diabetic patients due to a founder-effect in a local population

A high proportion of the female patients who are members of maturity onset diabetes of the young (MODY) pedigrees, and whose diabetes mellitus is due to a glucokinase mutation, originally presented with gestational diabetes. To establish whether glucokinase mutations could be a common cause of gestational diabetes, we studied 50 subjects who presented with gestational diabetes and on follow-up had hyperglycaemia (5.5-10.0 mmol/l). Screening for glucokinase mutations using single-stranded conformational polymorphism (SSCP) analysis detected a missense mutation at position 299 (Gly299-->Arg) in three subjects. As two pedigrees in the Oxford area had the same glucokinase mutation, we suspected the role of a founder-effect, and carried out pedigree extension, haplotype construction (using microsatellite markers GCK1 and GCK2) and mutation screening of at-risk subjects from the same geographical area. One of the gestational diabetic subjects was found to be related to one of the previous pedigrees via her paternal grandmother. Subjects with the mutation were found to have the Z + 4/2 (GCK1/ GCK2) haplotype, suggesting that the observed high prevalence of the Gly299-->Arg glucokinase mutation in the Oxford region was due to a founder-effect. Since glucokinase mutations predominantly induce subclinical hyperglycaemia, it is likely that in the locality of other pedigrees there will be undiagnosed subjects with the same glucokinase mutation, which remains undetected unless pregnancy occurs.

Clinical characteristics of subjects with a missense mutation in glucokinase

The clinical characteristics of subjects with a missense glucokinase mutation, gly299-->arg, were studied in a large pedigree, BX, initially characterized by some members having Maturity Onset Diabetes of the Young (MODY). Glucose tolerance, beta cell function and insulin sensitivity were measured with Homeostasis Model Assessment (HOMA) and with a 'Continuous Infusion of Glucose with Model Assessment' (CIGMA) test. Diabetic complications were clinically assessed. Subjects with glucokinase gly299-->arg were the same age, height, and obesity as the subjects without the mutation. Diabetes was usually asymptomatic at diagnosis and was treated with diet alone in 15 of the 18 subjects. Five of the 11 adult females had been diagnosed when they developed gestational diabetes. The fasting plasma glucose concentrations at the time of study were 4.3-12.6 mmol l-1, with the higher levels being in the more obese (p < 0.05) and in the older subjects (p < 0.05). In subjects with the mutation, beta cell function was impaired, being geometric mean 63% (normal-100%) compared with 126% in the subjects without the mutation (p < 0.001) measured by HOMA and in a subset assessed by CIGMA 59% and 127% (p < 0.01), respectively. There was no difference in fasting insulin concentrations, insulin sensitivity, lipid concentrations or blood pressure between the groups. The haemoglobin A1c was raised (mean 6.5% compared with 5.5% in the subjects without the mutation), but microvascular and macrovascular complications were uncommon. The subjects with the mutation did not have microalbuminuria but had an impaired vibration perception threshold compared with subjects without the mutation.(ABSTRACT TRUNCATED AT 250 WORDS)

Availability of type II diabetic families for detection of diabetes susceptibility genes

Type II diabetes is a familial disorder, as evidenced by the increased prevalence in monozygotic cotwins and first-degree relatives of affected subjects; however, its genetic etiology is largely unknown. Well-characterized pedigrees are an essential resource for the study of susceptibility genes for type II diabetes. This study describes a 5-yr search for type II diabetic families in Oxfordshire, U.K. We interviewed 950 type II diabetic subjects concerning the availability of first-degree relatives; 127 Caucasian families ascertained through a proband with type II diabetes were studied, and 589 first-degree relatives were characterized. Three large pedigrees with maturity-onset diabetes of the young, and 8 multiplex multigenerational type II diabetic pedigrees were identified. We identified 12 sib-pairs in which both siblings had type II diabetes; however, only 7 sib-pairs had both parents alive, and 2 of these had both parents affected. If one also considers one sib having diabetes and one sib having glucose intolerance as being an affected sib-pair, we identified 30 sib-pairs of which 7 had both parents affected and probably had bilineal inheritance. We identified 76 complete nuclear families with both parents and offspring available for study, but only 6 were of optimal structure for linkage analysis. In conclusion, multiplex pedigrees and type II diabetic sib-pairs with living parents are uncommon, and their ascertainment requires a substantial investment of resources. Large-scale collaborative multicenter initiatives would be needed to collect a large resource of family material for the study of susceptibility genes for type II diabetes.

Linkage analysis of glucokinase gene with NIDDM in Caucasian pedigrees

NIDDM has a strong genetic component, as evidenced by the high level of concordance between identical twins. The nature of the genetic predisposition has remained largely unknown. Recently, the glucokinase gene locus on chromosome 7p has been shown to be linked to a subtype of NIDDM known as MODY in French and British pedigrees, and glucokinase mutations have been identified. To study the relationship between the glucokinase gene and NIDDM, we performed a linkage analysis in 12 Caucasian pedigrees ascertained through a proband with classical NIDDM. The LINKAGE program was used under four models, including autosomal dominant and recessive, with individuals with glucose intolerance counted as either affected or of unknown status. Linkage was significantly rejected with the dominant models (LOD scores -4.65, -4.25), and was unlikely with the recessive model when glucose intolerance was considered as affected (LOD score -1.38). These findings suggest that mutations in or near the glucokinase gene are unlikely to be the major cause of the inherited predisposition to NIDDM in Caucasian pedigrees, but do not exclude a role for this locus with a polygenic model, or a major role in some pedigrees.