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BACKGROUND: Hypothesis-free signal detection (HFSD) methods such as tree-based scan statistics (TBSS) applied to longitudinal electronic healthcare data (EHD) are increasingly used in safety monitoring. However, challenges may arise in interpreting HFSD results alongside results from disproportionality analysis of spontaneous reporting. RESEARCH DESIGN AND METHODS: Using the anti-diabetes drug insulin glargine (Lantus®) we apply two different tree-based scan designs using TreeScan™ software on retrospective EHD and compare the results to one another as well as to results from a disproportionality analysis using SRD. RESULTS: The self-controlled tree temporal scan method produced the larger number of alerts relative to propensity-score matched approach; however, far fewer alerts were observed when analyses were limited to EHD in inpatient/emergency room settings only. Very few reference adverse events were observed using TBSS methods on EHD relative to disproportionality methods in SRD. CONCLUSION: Differences in detected alerts between TBSS methods and between TBSS and disproportionality analysis of SRD are likely attributable to differences in data, comparator, and study design. Our results suggest that HFDS methods like TBSS applied to EHD may complement more traditional approaches such as disproportionality analysis of SRD to provide a more complete picture of product safety in the post-approval setting.

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BACKGROUND: There are four distinguishable types of THA devices in wide use, as defined by the femoral and acetabular bearing surfaces: metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), metal-on-metal (MoM), and ceramic-on-ceramic (CoC). Metallic head THAs (MoP and MoM) can potentially induce cardiac toxicity because cobalt species, generated at the head-neck trunnion, and in the case of MoM devices, at the articular surface as well, can be absorbed systemically. However, studies have provided inconsistent results. QUESTIONS/PURPOSES: The purpose of this study was to assess the risk of dilated cardiomyopathy (DCM) or heart failure (HF) associated with metallic head THAs using data from the French national health insurance databases. METHODS: Between 2008 and 2011 in France, 399,968 patients ≥ 55 years had a first THA. A total of 127,481 were excluded after we applied the exclusion criteria regarding arthroplasty and 17,137 as a result of a history of DCM/HF, recorded in the French national health insurance reimbursement databases, between January 1, 2006, and the date of inclusion. The final cohort included 255,350 individuals (43% men; mean age 72 ± 9 years). Of them, 93,581 (37%) had been implanted with MoP, 58,095 (23%) with CoP, 11,298 (4%) with MoM, and 92,376 (36%) with CoC THAs. Patients were followed until December 2015. Patients with incident DCM/HF were identified by a new entitlement to the long-term disease scheme or a first hospitalization with a diagnosis of DCM or HF. MoP and CoP THAs are generally implanted in old patients, whereas MoM and CoC are mostly indicated in young, active male patients. Thus, to consider the specific indications of the bearing couples, analyses were separately performed in two distinct subcohorts, one comprising patients with MoP or CoP and one comprising patients with MoM or CoC THA. In each subcohort, the DCM/HF risk was compared between patients with metallic head versus nonmetallic head THAs (MoP versus CoP, MoM versus CoC). Hazard ratios (adjusted HRs) of incident DCM/HF were estimated using Cox models adjusted for baseline sex, age, THA characteristics (fixation technique with cement, use of a modular femoral neck), and comorbidities at baseline. Cox models were stratified by sex and age. RESULTS: The crude incidence of DCM/HF per 100 person-years was 2.4 in patients with MoP, 1.8 with CoP, 1.2 with MoM, and 1.1 with CoC THAs. Overall, metallic head THAs were associated with a slight increase in DCM/HF risk (MoP versus CoP: adjusted HR, 1.08; 95% confidence interval [CI], 1.05-1.12; p < 0.001; MoM versus CoC: adjusted HR, 1.11; 95% CI, 1.03-1.19; p = 0.007). In the MoM-CoC subcohort, the risk tended to be more pronounced with MoM versus CoC THAs in women (MoM versus CoC: adjusted HR, 1.20; 95% CI, 1.07-1.35; p = 0.002) and patients aged ≥ 75 years (MoM versus CoC: adjusted HR, 1.16; 95% CI, 1.04-1.29; p = 0.009). CONCLUSIONS: Metallic head THAs were associated with a slightly increased DCM/HF risk, especially with MoM in women and older patients. Some caveats should be mentioned: severity of DCM or HF was not available and residual confounding cannot be ruled out despite considering many covariates. Our findings suggest that cardiac function should be regularly monitored in patients with metallic head THAs. Further investigations should be planned on large international cohorts. LEVEL OF EVIDENCE: Level III, therapeutic study.

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BACKGROUND: Both surgeon and hospital procedure volumes have been found to be associated with total hip arthroplasty (THA) outcomes. However, little research has been conducted on the relative influence. We studied the association between THA survivorship and both hospital and surgeon procedure volumes, considering their relative impact. METHODS: A population-based cohort included all patients aged ≥40 years having received a unilateral primary THA from 2010 to 2011, from the French National Health Insurance Database. Patients were followed up until the end of 2014. The outcome was THA revision. Exposures of interest were procedure volumes, divided into tertiles: <1.5, 1.5-4, >4 and <7, 7-15, >15 procedures per month defined as low, medium, and high volumes for surgeon and hospital, respectively. RESULTS: The cohort had 62,906 patients, with mean age 69 years and women 57%. Mean surgeon and hospital volumes were 8 and 23 procedures per month, respectively, and 5%, 72%, 22% and 7%, 28%, 65% of THAs were implanted by a low-, medium-, and high-volume surgeon or in a low-, medium-, and high-volume hospital, respectively. Median follow-up was 45 months (range, 0-57 months). In multivariate analysis, adjusted for both surgeon and hospital volumes, for patient and THA characteristics, a lower surgeon volume was associated with poorer THA survivorship (adjusted hazard ratio [aHR] = 1.19; 95% confidence interval [CI], 1.07-1.34 and aHR = 1.70; 95% CI, 1.40-2.05, for medium- and low-volume surgeon, respectively, compared with that of high volume), whereas hospital volume was not. CONCLUSIONS: This study brings evidence to support the notion that THAs performed by high-volume surgeons in French private hospitals have higher survivorship in the first 4 years.

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BACKGROUND: Exchangeable neck stems, defined as those with a dual taper (that is, a modular junction between the femoral head and the femoral neck and an additional junction between the neck and the stem body), were introduced in THA to improve restoration of joint biomechanics (restoring anteversion, offset, and limb length) and reduce the risk of dislocation. However exchangeable necks have been reported to result in adverse effects such as stem fractures and acute local tissue reaction. Whether they result in a net improvement to or impairment of reconstructive survivorship remains controversial. QUESTIONS/PURPOSES: (1) To compare the prosthetic survivorship and all-cause revision risk of exchangeable femoral neck THAs versus fixed neck THAs, taking known prosthetic revision risk factors into account; and (2) to compare the cause-specific revision risk of exchangeable femoral neck THAs versus fixed neck THAs, adjusting for known prosthetic risk factors. METHODS: Using French national health-insurance databases, we identified all French patients older than 40 years who underwent primary THA from 2009 through 2012. To ensure accuracy of the data, we considered only beneficiaries of the general insurance scheme (approximately 77% of the population). Characteristics of the prosthesis and the patients receiving an exchangeable femoral neck THA were compared with those receiving a fixed femoral neck THA (defined as femoral stem with only the head being exchangeable). Revision was the event of interest. Followup started on the date the THA was performed, until the patient experienced revision, died, was lost to followup, or until the followup period ended (December 31, 2014), whichever came first. Competing risk THA survivorship was calculated and compared (purpose 1), as were cause-specific Cox regression models (purpose 2). The study cohort included 324,108 individuals with a mean age of 77 years. A total of 24% underwent THA for acute trauma, and 3% of the group received an exchangeable neck THA. During the median 45-month followup (mean, 42 months; minimum, 1 day; maximum, 6 years), 11,968 individuals underwent prosthetic revision. RESULTS: The cumulative revision incidence was 6.5% (95% CI, 5.8%-7.3%) for exchangeable neck THAs versus 4.7% (95% CI, 4.6%-4.8%) for fixed neck THAs (p < 0.001). After controlling for potential confounding variables including age, sex, comorbidities, indication for THA, cementation, bearing surface, and the characteristics of the center where the implantation was performed, we found that the exchangeable femoral neck THA was associated with an increased hazard ratio (HR) of revision of 1.26 (95% CI, 1.14-1.38; p < 0.001) compared with the fixed neck THA. When dealing with cause-specific revision, exchangeable neck THAs had a higher incidence of revision for implant failure or periprosthetic fracture, and for mechanical complications; adjusted HRs were, respectively, 1.68 (95% CI, 1.24-2.27; p < 0.001) and 1.27 (95% CI, 1.13-1.43; p < 0.001), for exchangeable neck THAs compared with fixed ones. CONCLUSIONS: Exchangeable neck THAs had poorer survivorship independent of other prosthetic revision risk factors. Accordingly, expected anatomic and functional benefits should be carefully assessed before choosing this design. LEVEL OF EVIDENCE: Level III, therapeutic study.

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BACKGROUND: Total hip replacement (THR) is successful in treating hip arthritis. Prosthetic survivorship may depend on the medications taken by the patient; particularly, the role of benzodiazepines and related drugs (Z-drugs) with THR revision has been poorly investigated. Our objective was to compare THR short-term survivorship according to level of exposure to benzodiazepine and Z-drugs. DESIGN, SETTING AND PARTICIPANTS: All French patients aged 40 years or older, having undergone primary THR from January 1, 2009, through December 31, 2012, for arthritis according to French national health insurance databases were included in the cohort. Outcome of interest was THR revision, including any surgical procedure in which the implant or any component was changed or removed. Follow-up started the day the primary THR was performed. Observations were right-censored on December 31, 2014, if neither revision nor death had yet occurred. Exposure of interest was the cumulative defined daily doses per day (cDDD/day) of benzodiazepines and Z-drugs dispensed within 6 months before or after inclusion. We defined four exposure groups; cDDD/d = 0: unexposed; <0.08: low exposure;] 0.08-0.38]: medium exposure; >0.38: high exposure. THR survivorship was assessed according to level of exposure to benzodiazepines and Z-drugs in univariate and multivariate Cox models adjusted for patient, THR and implanting center characteristics. RESULTS: The study cohort comprised 246,940 individuals: mean age at baseline, 69.9 years; women, 57.9%; unexposed: 51.7%; low exposure: 16.7%; medium exposure: 15.9%; and high exposure: 15.7%. During the median 45-month follow-up, 9043 individuals underwent prosthetic revision. Adjusted hazard ratios in low, medium and high exposed groups were 1.18 (95%CI, 1.12-1.26; P<0.001), 1.32 (95%CI, 1.24-1.40; P<0.001) and 1.37 (95%CI, 1.29-1.45; P<0.001), respectively, compared to unexposed. CONCLUSION AND RELEVANCE: Exposure to benzodiazepines and Z-drugs is associated with an increased risk of THR revision, with a dose-response relationship. Cautious prescribing might be needed as well as careful history examination and assessment of risk for patients with a hip prosthesis.

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IMPORTANCE: Total hip replacement (THR) is successful in treating hip arthritis. Prosthetic survivorship may depend on characteristics of the implant, notably THR fixation technique and bearing surface type. OBJECTIVE: To compare THR short-term survivorship according to cement type and bearing surface. DESIGN, SETTING, AND PARTICIPANTS: The cohort included all French patients aged 40 years or older covered by the general scheme of the French national health insurance system who had undergone THR from April 1, 2010, through December 31, 2011, for arthritis, according to French national health insurance databases. The cohort was followed up until December 31, 2013. The THR survivorship was assessed according to cement type and bearing surface in univariate and multivariate Cox proportional hazards regression models adjusted for patient and implanting center characteristics. EXPOSURES: Antibiotic-free cemented THRs and antibiotic-impregnated cemented THRs were compared with uncemented THRs. Ceramic-on-ceramic (CoC), ceramic-on-polyethylene (CoP), and metal-on-metal (MoM) THRs were compared with metal-on-polyethylene (MoP) THRs. MAIN OUTCOMES AND MEASURES: Revision, including any surgical reintervention in which the implant or any of its components was changed or removed. RESULTS: The study cohort comprised 100 191 individuals: mean age at baseline, 69.5 years; women, 56.6%; uncemented THR, 74.8%; antibiotic-free cemented THR, 3.8%; antibiotic-impregnated cemented THR, 21.4%; CoC, 40.9%; MoP, 33.9%; CoP, 20.8%; and MoM, 4.4%. During the median 33-month follow-up period, 3142 individuals underwent prosthetic revision. Antibiotic-impregnated cemented THRs had a better prognosis than uncemented THRs: cumulative revision rates were 2.4% and 3.3%, respectively (P < .001), and the multivariate adjusted hazard ratio was 0.75 (95% CI, 0.67-0.84; P < .001). This association was particularly significant in women. The CoP and CoC THRs were no different from the MoP THR. The MoM THR had slightly shorter survivorship compared with the MoP THR (adjusted hazard ratio, 1.20; 95% CI, 1.01-1.43; P < .001). CONCLUSIONS AND RELEVANCE: Characteristics of THR are related to early prosthetic revision: antibiotic-impregnated cemented THRs have a better prognosis and MoM THRs a worse one. These findings are useful in helping surgeons select a THR fixation technique and helpful for both patient and surgeon in the decision-making process.

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Transmission of hepatitis C virus between hemodialysis patients occurs mainly between the patients treated simultaneously in the same sector or in the same room. The other mode of viral transmission occurs between two patients treated successively with the same hemodialysis generator-monitor and sharing the same environment. One of the vectors of this last mode of transmission could be the contamination of the system of measurement of pressure of the extracorporal blood circuit. In July 2004, the French health products safety agency (Agence française de sécurité sanitaire des produits de santé, Afssaps) published a recommendation on these systems of measurement of pressure. i) The recommendation points out the optional preventive measures that users and manufacturers can carry out: (a) the manufacturers can propose tight systems of measurement of pressure, based on the deformation of a device; (b) the users can add a second protective filter on the external tubing connecting the blood circuit to the machine; (c) the manufacturers can add additional protective filters on the internal tubings of the machine. ii)The recommendation indicates the actions to be carried out obligatorily in the event of backward flow of blood in the last external protective filter: the soiled filter must be replaced and the causes of the backward flow must be analyzed and corrected; after the session, the monitor must be taken out of the unit and checked by a technician. The technician must replace all the elements located downstream from a soiled protective filter: tubings, drip chamber level control system, and pressure transducer. When these elements are protected by internal filters, only tubings and the first internal filter not soiled must be replaced. Precautions with regard to the systems of measurement of pressure must supplement standard precautions of hygiene essential in hemodialysis units.

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