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1.
J Affect Disord ; 295: 1310-1318, 2021 12 01.
Article in English | MEDLINE | ID: mdl-34706445

ABSTRACT

BACKGROUND: Patients with depression and comorbid obesity may be more prone to weight modulating and cardiovascular side effects of selected antidepressants (AD). It is important to ascertain whether these AD prescriptions differ by patient weight status. METHODS: Canadian Primary Care Sentinel Surveillance Network (CPCSSN) electronic medical records were used. Participants were adults with depression prescribed an AD in 2000-2016, with weight categories established before the first prescription. Logistic regression and mixed effects models were applied to examine associations between obesity and AD prescribing, adjusted for sex, age, and comorbidities. Machine learning algorithm random forest (RF) was used to evaluate the importance of weight in predicting prescribing patterns. RESULTS: Of 26,571 participants, 72.4% were women, mean age was 38.9 years (standard deviation (SD)=14.2) and mean BMI 27.0 kg/m2 (SD = 6.5); 9.5% had ≥ 1 comorbidity. Patients with obesity, compared to normal weight patients, were more likely to receive bupropion (adjusted odds ratio (aOR) 1.24, 95%CI: 1.09,1.42), fluoxetine (aOR 1.14, 95%CI: 0.97,1.34), and amitriptyline (aOR 1.13, 95%CI: 0.93,1.36), and less likely to receive mirtazapine (aOR 0.55, 95%CI: 0.44,0.68) and escitalopram (aOR 0.88, 95%CI: 0.80, 0.97). RF analysis showed that weight was among the most important predictors of prescribing patterns, equivalent to age and more important than sex. CONCLUSIONS: AD prescribing patterns for patients with obesity appear to be different for selected AD types, including AD known for their weight-modulating and cardiovascular side effects. Longitudinal studies are needed to examine whether these prescribing patterns are associated with significant health outcomes.


Subject(s)
Antidepressive Agents , Citalopram , Adult , Antidepressive Agents/adverse effects , Canada , Female , Humans , Mirtazapine , Obesity/chemically induced , Obesity/epidemiology
2.
Curr Oncol ; 23(2): 81-90, 2016 Apr.
Article in English | MEDLINE | ID: mdl-27122972

ABSTRACT

BACKGROUND: Cancer quality indicators have previously been described for a single tumour site or a single treatment modality, or according to distinct data sources. Our objective was to identify cancer quality indicators across all treatment modalities specific to breast, prostate, colorectal, and lung cancer. METHODS: Candidate indicators for each tumour site were extracted from the relevant literature and rated in a modified Delphi approach by multidisciplinary groups of expert clinicians from 3 clinical cancer programs. All rating rounds were conducted by e-mail, except for one that was conducted as a face-to-face expert panel meeting, thus modifying the original Delphi technique. Four high-level indicators were chosen for immediate data collection. A list of confounding variables was also constructed in a separate literature review. RESULTS: A total of 156 candidate indicators were identified for breast cancer, 68 for colorectal cancer, 40 for lung cancer, and 43 for prostate cancer. Iterative rounds of ratings led to a final list of 20 evidence- and consensus-based indicators each for colorectal and lung cancer, and 19 each for breast and prostate cancer. Approximately 30 clinicians participated in the selection of the breast, lung, and prostate indicators; approximately 50 clinicians participated in the selection of the colorectal indicators. CONCLUSIONS: The modified Delphi approach that incorporates an in-person meeting of expert clinicians is an effective and efficient method for performance indicator selection and offers the added benefit of optimal clinician engagement. The finalized indicator lists for each tumour site, together with salient confounding variables, can be directly adopted (or adapted) for deployment within a performance improvement program.

3.
Br Dent J ; 220(3): 117-20, 2016 Feb 12.
Article in English | MEDLINE | ID: mdl-26868800

ABSTRACT

AIM: This paper aims to compare the effectiveness of articaine buccal infiltrations (BIs) and lidocaine inferior alveolar nerve blocks (IANBs) for inducing pulpal anaesthesia in mandibular molars. METHOD: Studies which compared articaine BIs with lidocaine IANBs were identified by completing a full literature search using the MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials databases. Only studies that used permanent mandibular molars were included. Two papers were accepted for appraisal. RESULTS: It was found that 55.6-69.2% and 65.4-70.4% of lidocaine IANBs and articaine BIs were successful, respectively. Neither study was able to determine a significant difference between the two techniques. CONCLUSIONS: Articaine BIs are no more effective than lidocaine IANBs and the decision of which method to practice should be based on patient selection, cost and time efficiency. The studies present a number of weaknesses in their design, hence, the level of evidence they provide is inconclusive. Further investigation in this field is warranted.


Subject(s)
Anesthesia, Dental/methods , Anesthetics, Local , Carticaine , Lidocaine , Nerve Block/methods , Administration, Buccal , Anesthesia, Local/methods , Anesthetics, Local/administration & dosage , Carticaine/administration & dosage , Humans , Lidocaine/administration & dosage , Mandibular Nerve
4.
Clin Radiol ; 71(3): 211-9, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26706230

ABSTRACT

AIM: To validate the role of nuclear medicine (NM) imaging in hip periprosthetic joint infection (PJI) of hip arthroplasties. MATERIALS AND METHODS: This was a retrospective study of 235 consecutive patients referred to NM for investigation of a symptomatic hip prosthesis. Imaging comprised Tc-99m bone scintigraphy, In-111 white cell scintigraphy, and bone marrow scintigraphy if required. Imaging findings were compared with intraoperative microbiology and histology, clinical findings and follow up for ≥ 24 months. RESULTS: There were 14 exclusions. Of the 221 remaining patients, there were 16 true positives, one false positive, 200 true negatives, and four false negatives. The algorithm used at this centre demonstrated an accuracy of 97.7% with high specificity of 99.5% and sensitivity of 80%. CONCLUSION: When modern NM techniques and accurate reporting criteria are used, scintigraphy is an effective tool for diagnosing PJI of the hip. NM is only given a marginal role in the recent American Association of Orthopedic Surgeons guidelines, and the orthopaedic community should reconsider their evaluation of this technique.


Subject(s)
Arthroplasty, Replacement, Hip/adverse effects , Hip Prosthesis/adverse effects , Prosthesis-Related Infections/diagnostic imaging , Tomography, Emission-Computed, Single-Photon , Adult , Aged , Aged, 80 and over , Algorithms , Biomarkers/blood , Female , Humans , Male , Middle Aged , Radiopharmaceuticals , Retrospective Studies , Sensitivity and Specificity , Technetium Tc 99m Medronate/analogs & derivatives
5.
Int J Tuberc Lung Dis ; 18(12): 1449-54, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25517810

ABSTRACT

SETTING: Latent tuberculous infection (LTBI) remains a significant source of new active tuberculosis cases. Recent guidelines encourage primary care physicians to prescribe LTBI treatment; however, there have been no investigations into the impact on treatment completion. OBJECTIVE: To estimate LTBI treatment initiation and completion rates by primary care physicians. DESIGN: A historical cohort study was conducted with Quebec residents dispensed isoniazid (INH) between 1 January 1998 and 31 December 2005. Information was obtained from administrative health insurance data. Regression modeling was used to estimate the association of completion rates with prescribing physician specialty, after adjustment for initial health status and other patient characteristics. RESULTS: A total of 14,753 people were dispensed INH for LTBI treatment. Primary care physicians initiated 3863 (26%) treatments. This proportion decreased from 28.7% in 1998 to 21.1% in 2005. Patients initiated on treatment by primary care physicians were less likely to complete treatment (OR 0.79, 95%CI 0.72-0.86). Only 5977 (40.5%) patients completed treatment; the average treatment duration of the primary care physician group was 11 days less (P < 0.0001). CONCLUSION: Primary care physicians initiated a substantial number of LTBI treatments, but less than half of patients completed treatment regardless of the physician specialty. Primary care physicians should be supported to enhance treatment completion.


Subject(s)
Antitubercular Agents/therapeutic use , Isoniazid/therapeutic use , Latent Tuberculosis/drug therapy , Physician's Role , Physicians, Primary Care/trends , Practice Patterns, Physicians'/trends , Primary Health Care/trends , Adolescent , Adult , Aged , Aged, 80 and over , Chi-Square Distribution , Child , Child, Preschool , Drug Prescriptions , Female , Guideline Adherence , Humans , Infant , Latent Tuberculosis/diagnosis , Latent Tuberculosis/epidemiology , Logistic Models , Male , Medication Adherence , Middle Aged , Odds Ratio , Physicians, Primary Care/standards , Practice Guidelines as Topic , Practice Patterns, Physicians'/standards , Primary Health Care/standards , Quebec/epidemiology , Retrospective Studies , Time Factors , Treatment Outcome , Young Adult
6.
Bone Joint J ; 96-B(2): 188-94, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24493183

ABSTRACT

Impaction bone grafting for the reconstitution of bone stock in revision hip surgery has been used for nearly 30 years. Between 1995 and 2001 we used this technique in acetabular reconstruction, in combination with a cemented component, in 304 hips in 292 patients revised for aseptic loosening. The only additional supports used were stainless steel meshes placed against the medial wall or laterally around the acetabular rim to contain the graft. All Paprosky grades of defect were included. Clinical and radiographic outcomes were collected in surviving patients at a minimum of ten years after the index operation. Mean follow-up was 12.4 years (sd 1.5) (10.0 to 16.0). Kaplan-Meier survival with revision for aseptic loosening as the endpoint was 85.9% (95% CI 81.0 to 90.8) at 13.5 years. Clinical scores for pain relief remained satisfactory, and there was no difference in clinical scores between cups that appeared stable and those that appeared radiologically loose.


Subject(s)
Acetabulum/surgery , Arthroplasty, Replacement, Hip/methods , Bone Cements , Bone Transplantation/methods , Femur Head/transplantation , Forecasting , Hip Prosthesis , Adult , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Male , Middle Aged , Prosthesis Failure , Reoperation/methods , Retrospective Studies , Treatment Outcome
7.
Clin. transl. oncol. (Print) ; 15(9): 720-724, sept. 2013. tab, ilus
Article in English | IBECS | ID: ibc-127491

ABSTRACT

BACKGROUND AND PURPOSE: External beam radiation therapy with concurrent chemotherapy (CRT) is widely used for the treatment of unresectable pancreatic cancer. Noncoplanar (NCP) 3D conformal radiotherapy (3DCRT) and coplanar (CP) IMRT have been reported to lower the radiation dose to organs at risk (OARs). The purpose of this article is to examine the utility of noncoplanar beam angles in IMRT for the management of pancreatic cancer. MATERIALS AND METHODS: Sixteen patients who were treated with CRT for unresectable adenocarcinoma of the pancreatic head or neck were re-planned using CP and NCP beams in 3DCRT and IMRT with the Varian Eclipse treatment planning system. RESULTS: Compared to CP IMRT, NCP IMRT had similar target coverage with slightly increased maximum point dose, 5,799 versus 5,775 cGy (p = 0.008). NCP IMRT resulted in lower mean kidney dose, 787 versus 1,210 cGy (p < 0.0001) and higher mean liver dose, 1,208 versus 1,061 cGy (p < 0.0001). Also, NCP IMRT resulted in similar mean stomach dose, 1,257 versus 1,248 cGy (p = 0.86) but slightly higher mean small bowel dose, 981 versus 866 cGy (p < 0.0001). CONCLUSIONS: The NCP IMRT was able to significantly decrease bilateral kidney dose, but did not improve other dose-volume criteria. The use of NCP beam angles is preferred only in patients with risk factors for treatment-related kidney dysfunction (AU)


Subject(s)
Humans , Male , Female , Pancreatic Neoplasms/drug therapy , Pancreatic Neoplasms/metabolism , Pancreatic Neoplasms/radiotherapy , Pancreatic Neoplasms/diagnosis , Kidney/abnormalities , Liver/abnormalities , Intestine, Small/radiation effects
8.
Clin Transl Oncol ; 15(9): 720-4, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23359183

ABSTRACT

BACKGROUND AND PURPOSE: External beam radiation therapy with concurrent chemotherapy (CRT) is widely used for the treatment of unresectable pancreatic cancer. Noncoplanar (NCP) 3D conformal radiotherapy (3DCRT) and coplanar (CP) IMRT have been reported to lower the radiation dose to organs at risk (OARs). The purpose of this article is to examine the utility of noncoplanar beam angles in IMRT for the management of pancreatic cancer. MATERIALS AND METHODS: Sixteen patients who were treated with CRT for unresectable adenocarcinoma of the pancreatic head or neck were re-planned using CP and NCP beams in 3DCRT and IMRT with the Varian Eclipse treatment planning system. RESULTS: Compared to CP IMRT, NCP IMRT had similar target coverage with slightly increased maximum point dose, 5,799 versus 5,775 cGy (p = 0.008). NCP IMRT resulted in lower mean kidney dose, 787 versus 1,210 cGy (p < 0.0001) and higher mean liver dose, 1,208 versus 1,061 cGy (p < 0.0001). Also, NCP IMRT resulted in similar mean stomach dose, 1,257 versus 1,248 cGy (p = 0.86) but slightly higher mean small bowel dose, 981 versus 866 cGy (p < 0.0001). CONCLUSIONS: The NCP IMRT was able to significantly decrease bilateral kidney dose, but did not improve other dose-volume criteria. The use of NCP beam angles is preferred only in patients with risk factors for treatment-related kidney dysfunction.


Subject(s)
Adenocarcinoma/radiotherapy , Pancreatic Neoplasms/radiotherapy , Radiotherapy, Intensity-Modulated/instrumentation , Radiotherapy, Intensity-Modulated/methods , Algorithms , Humans , Kidney/radiation effects , Organs at Risk , Radiometry/methods , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted/methods , Risk Factors
9.
J Lab Autom ; 16(1): 82-9, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21609688

ABSTRACT

In this article, we present the Laboratory Inventory Network Application (LINA), a software system that assists research laboratories in keeping track of their collections of biologically relevant materials. This open source application uses relational Microsoft Access database technology as a back end and a Microsoft .NET application as a front end. Preconstructed table templates are provided that contain standardized and customizable data fields. As new samples are added to the inventory, each is provided with a unique laboratory identifier, which is assigned automatically and sequentially, allowing rapid retrieval when a given reagent is required. The LINA contains a number of useful search tools including a general search, which allows database searches using up to four user-defined criteria. The LINA represents an easily implemented and useful organizational tool for biological laboratories with large numbers of strains, clones, or other reagents.


Subject(s)
Biological Specimen Banks , Database Management Systems , Databases as Topic , Electronic Data Processing/methods , Software , Bacteria , Cell Line , Fungi , Humans , Oligonucleotides
10.
Med Eng Phys ; 30(8): 1042-8, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18280197

ABSTRACT

The presence of an intra-articular pump has been proposed as a central mechanism in the process of osteolysis and aseptic loosening of hip arthroplasty. It is not known if this pump exists and its mechanism remains uncharacterised. This study describes a new in vitro model of a cemented femoral stem in which cement/stem interface fluid pressures can be reliably measured under dynamic loads simulating stair climbing. A stem pump mechanism was found that generates both positive and negative clinically significant pressures (mean pressure ranges 5000-17,000 Pa). The timing of pressure peaks on the anterior and posterior aspects of the stem were in anti-phase, giving rise to oscillatory pressure gradients and potentially generating oscillatory fluid flows during the simulated physiological load cycle. The pump mechanism was shown to occur at the interface of a newly implanted polished double-tapered stem and emphasizes the importance of a complete mantle to protect the femoral bone from the raised fluid pressures.


Subject(s)
Arthroplasty, Replacement, Hip/instrumentation , Arthroplasty, Replacement, Hip/methods , Cementation , Femur/physiology , Models, Biological , Humans , Pressure
11.
Aust Vet J ; 81(5): 271-2, 2003 May.
Article in English | MEDLINE | ID: mdl-15084035

ABSTRACT

A female breeding alpaca with acute lameness of the left hindleg was diagnosed with a craniodorsal coxofemoral luxation. Repair was achieved using extracapsular stabilisation. Two nylon sutures were passed through a hole drilled in the femoral neck and anchored to the dorsal acetabulum using two screws and two spiked washers. A metal crimp was used to tighten and maintain the sutures. Postoperatively the alpaca was confined to a stall for 4 weeks before being returned to a paddock. At 6 months after surgery the alpaca was free of lameness and was successfully mated.


Subject(s)
Camelids, New World , Hip Dislocation/veterinary , Animals , Bone Screws/veterinary , Coccyx , Diagnosis, Differential , Female , Femur , Hip Dislocation/complications , Hip Dislocation/diagnosis , Hip Dislocation/diagnostic imaging , Hip Dislocation/surgery , Lameness, Animal/etiology , Osteotomy/veterinary , Radiography , Suture Techniques/veterinary
12.
AMIA Annu Symp Proc ; : 786, 2003.
Article in English | MEDLINE | ID: mdl-14728290

ABSTRACT

The Medical Office for the Twenty First Century (MOXXI) is a research project testing the potential benefits of an electronic prescription and drug management system for primary care physicians. This system includes a dynamic electronic pad for prescription entry with fields for treatment indications; a drug profiler with a graphic representation of the list of prescription medications purchased in the last year; a refill compliance calculator; dates of emergency room visits and hospital admissions; cost of drugs dispensed; and an alert system that detects interactions among drugs, treatment duplications, and contraindications with certain allergies or specific diseases. One concern expressed by physicians that could influence uptake and acceptability is the increased time that may be required to use the system. User abilities are a factor in this process, as well as user interface, user training and system speed.


Subject(s)
Clinical Pharmacy Information Systems , Drug Therapy, Computer-Assisted , Medical Records Systems, Computerized , Physicians, Family , Computers, Handheld , Drug Prescriptions , Humans , Systems Integration , Task Performance and Analysis , User-Computer Interface
14.
J Hosp Infect ; 52(1): 68-70, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12372329

ABSTRACT

Twenty items of three jewellery types were studied. Finger rings, nose and ear piercings increased local surface bacterial counts when in situ, and especially after removal (P<0.0001). Although in the UK the National Association of Theatre Nurses' guidelines suggest that all jewellery should be removed before scrubbing, we suggest that jewellery worn on noses and ears should be left in situ and covered by masks and hats, respectively. The effect of jewellery on skin disinfection needs further study before guidelines can be made concerning finger rings.


Subject(s)
Bacteria/isolation & purification , Clothing , Nurses , Operating Rooms , Skin/microbiology , Female , Humans
15.
J Hosp Infect ; 50(4): 281-5, 2002 Apr.
Article in English | MEDLINE | ID: mdl-12014901

ABSTRACT

There is a paucity of data on the penetration of bacteria through surgical gowns during operations. A simple new method was developed, using Petri dishes filled with horse blood agar that were attached to the outside of the gown material. This was used to assess bacterial penetration through disposable spun-bonded polyester gowns and re-usable woven polyester gowns during normal use. There was a significant difference between the two gown types when tested in the axilla (P = 0.02), the groin (P = 0.02) and the peri-anal region (P < 0.01), with the disposable gowns performing to a higher standard. Re-usable gowns demonstrated variation in penetrability, and for this reason, may be unsuitable for use in orthopaedic implant surgery.


Subject(s)
Bacteria/isolation & purification , Equipment Contamination , Protective Clothing/microbiology , Disposable Equipment/microbiology , Humans , Operating Rooms
16.
J Hand Surg Am ; 26(4): 595-8, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11466630

ABSTRACT

Primary shortening of the flexor digitorum profundus tendon to the pollicized index finger was routinely performed during all congenital pollicizations over a 3-year period. Interphalangeal joint flexion of the pollicized digit was observed to begin within weeks after pollicization. The rebalancing of the pollicized long flexor musculotendinous unit has the potential for greater long-term strength.


Subject(s)
Fingers/surgery , Hand Deformities, Congenital/surgery , Orthopedic Procedures , Tendon Transfer/methods , Tendons/surgery , Thumb/abnormalities , Thumb/surgery , Adolescent , Child , Child, Preschool , Humans , Infant , Plastic Surgery Procedures/methods
17.
Ann Plast Surg ; 45(6): 607-11, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11128758

ABSTRACT

The tuberous breast deformity is one of the most challenging congenital breast anomalies. The nomenclature, classification, and treatment of this pathological condition have varied considerably. In this study, 16 patients with 23 tuberous breast deformities are evaluated. The breast deformities are classified according to the three-tier classification system used at the authors' institution. The treatment pattern is evaluated and a flexible algorithm is discussed for the treatment of the tuberous breast deformity.


Subject(s)
Breast/abnormalities , Breast/surgery , Mammaplasty/methods , Breast Diseases/classification , Breast Diseases/congenital , Female , Humans
18.
J Investig Med ; 48(3): 207-12, 2000 May.
Article in English | MEDLINE | ID: mdl-10822902

ABSTRACT

OBJECTIVE: To determine whether the ability of baseline clinical stage, viremia, and CD4 cell counts to predict mortality in HIV-1-infected patients changes with duration of follow-up. METHODS: Three hundred ninety-four patients were followed for an average of 29 months by the Swiss HIV Cohort Study, a practice-based registry of HIV-1-infected patients in Switzerland. Predictor variables were the baseline clinical stage, CD4 cell count, circulating HIV-1 RNA level, and the RNA/CD4 ratio; the outcome was death. The changes in relative risks of death over time were examined using survival models that extend the Cox model to allow for nonproportionality of hazards. RESULTS: During 949 person-years of follow-up, 169 patients died (mortality rate 17.8 per 100 person-years). Compared with clinical stage A, patients in stages B and C at baseline had much higher mortality rates in the subsequent year. The prognostic ability of stage C decayed over time (P = 0.03). By contrast, the relative risks associated with a 2-fold difference in CD4 counts remained remarkably stable, at approximately 0.6 (P = 0.81 for the time-dependence test). Relative hazards associated with a 10-fold difference in HIV RNA per milliliter and in HIV RNA per CD4 cell both tended to increase over time, but this trend failed to reach statistical significance (P = 0.21 and P = 0.08, respectively). CONCLUSIONS: Time-dependence patterns of prognostic ability varied widely among predictors, displaying gradual decay (clinical stage), stability (CD4 cells), and a trend to progressive increase (viremia). These results may affect clinical monitoring of HIV-infected patients and the interpretation of cohort studies of HIV-infected patients.


Subject(s)
HIV Infections/mortality , Adolescent , Adult , Aged , Biomarkers , CD4 Lymphocyte Count , Follow-Up Studies , HIV/genetics , HIV Infections/blood , Humans , Male , Middle Aged , Models, Statistical , Prognosis , Proportional Hazards Models , Prospective Studies , RNA, Viral/analysis , Risk , Survival Rate , Time Factors , Viremia
19.
Eur Respir J ; 15(1): 19-24, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10678615

ABSTRACT

A randomized double-blind placebo-controlled parallel group study with inhaled fluticasone propionate over 6 weeks, designed to quantify the beneficial effect on airway responsiveness, and so assess whether short pulses of intermittent prophylactic treatment might serve as an alternative means of managing mild asthma, is reported. The 20-50-yr-old participants, who were recruited from an epidemiological study of the general population, had never knowingly received any regular treatment for asthma. Fluticasone propionate at the maximum recommended dose level (2,000 microg daily) and placebo were administered via metered-dose inhalers, and airway responsiveness was quantified conventionally by the provocative dose of methacholine causing a 20% fall in forced expiratory volume in one second (FEV1) (PD20) at 2-week intervals during the treatment phase and at various intervals subsequently. Compared with placebo fluticasone propionate was associated with a highly significant decrease in airway responsiveness (1.9 doublings of the geometric mean PD20), which was maximal at the end of the 6-week treatment period. No persisting benefit was detectable at the next measurement 2 weeks later, or thereafter. Multiple linear regression analysis showed that the magnitude of the fluticasone propionate effect was significantly greater in males than in females (3.2 versus 1.2 doublings respectively of the geometric mean PD20), but was uninfluenced by current smoking, age or FEV1. In conclusion, in the absence of any possibility of tachyphylaxis, inhaled fluticasone propionate at this dose causes a steadily increasing improvement in airway responsiveness over a 6-week period, which is modified by sex but lost almost immediately on treatment cessation. Short pulses of intermittent prophylactic treatment would not, therefore, be useful as a means of managing mild asthma.


Subject(s)
Airway Resistance/drug effects , Androstadienes/administration & dosage , Anti-Asthmatic Agents/administration & dosage , Anti-Inflammatory Agents/administration & dosage , Asthma/drug therapy , Administration, Inhalation , Administration, Topical , Adult , Androstadienes/adverse effects , Anti-Asthmatic Agents/adverse effects , Anti-Inflammatory Agents/adverse effects , Asthma/diagnosis , Bronchial Provocation Tests , Double-Blind Method , Female , Fluticasone , Glucocorticoids , Humans , Male , Middle Aged , Sex Factors , Treatment Outcome
20.
Am J Epidemiol ; 150(11): 1188-200, 1999 Dec 01.
Article in English | MEDLINE | ID: mdl-10588079

ABSTRACT

The authors compare the performance of different regression models for censored survival data in modeling the impact of prognostic factors on all-cause mortality in colon cancer. The data were for 1,951 patients, who were diagnosed in 1977-1991, recorded by the Registry of Digestive Tumors of Côte d'Or, France, and followed for up to 15 years. Models include the Cox proportional hazards model and its three generalizations that allow for hazard ratio to change over time: 1) the piecewise model where hazard ratio is a step function; 2) the model with interaction between a predictor and a parametric function of time; and 3) the non-parametric regression spline model. Results illustrate the importance of accounting for non-proportionality of hazards, and some advantages of flexible non-parametric modeling of time-dependent effects. The authors provide empirical evidence for the dependence of the results of piecewise and parametric models on arbitrary a priori choices, regarding the number of time intervals and specific parametric function, which may lead to biased estimates and low statistical power. The authors demonstrate that a single, a priori selected spline model recovers a variety of patterns of changes in hazard ratio and fits better than other models, especially when the changes are non-monotonic, as in the case of cancer stages.


Subject(s)
Colonic Neoplasms/mortality , Models, Statistical , Survival Analysis , Aged , Female , Humans , Male , Multivariate Analysis , Prognosis , Proportional Hazards Models , Regression Analysis , Risk Factors
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