Pub Date : 2009-10-01DOI: 10.2105/9780875531939CH02
S. Coughlin
{"title":"Ethics in epidemiology: common misconceptions, paradoxes and unresolved questions.","authors":"S. Coughlin","doi":"10.2105/9780875531939CH02","DOIUrl":"https://doi.org/10.2105/9780875531939CH02","url":null,"abstract":"","PeriodicalId":80024,"journal":{"name":"Journal of epidemiology and biostatistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67593081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-12-27DOI: 10.1080/135952201317080409
E. Müller, T. Stürmer, H. Brenner
BACKGROUND Moderate alcohol consumption is known to affect several cardiovascular risk factors, including high density lipoprotein-cholesterol (HDL-C). Accurate measurement of alcohol intake in epidemiological studies is crucial for valid estimation of alcohol-related effects. METHODS We compared two widely used alcohol-intake assessment methods, a food frequency questionnaire (FFQ) and a 7-day diet record (DR) regarding the association between alcohol intake and HDL-C in the general population. RESULTS In a representative sample (842 men, 1103 women) of the population of former West Germany (VERA study), 75.6% of the participants reported drinking alcoholic beverages in the FFQ, whereas the percentage was 84.9% according to the DR. The median daily alcohol intake of consumers was 10.3 and 12.1 g, as assessed by the FFQ and the DR, respectively. There was moderate agreement between reported consumption levels ranked by quintiles according to FFQ and DR (kappa = 0.49). With both approaches alcohol intake showed a strong positive association with HDL-C in linear regression models. The estimated increases in HDL-C (mg dL(-1)) per gram alcohol per day from the FFQ and DR were 0.15 [95% confidence interval (CI): 0.12-0.18] and 0.14 (95% CI: 0.11-0.17), respectively. When participants with different classification of the amount of alcohol consumed by FFQ and DR were excluded from the analysis, the association between alcohol intake and HDL-C was more pronounced. DISCUSSION Our analyses suggest that both FFQ and DR lead to similar results regarding the alcohol-HDL-C association in the general population, despite major differences in the recorded prevalence of drinking and amount of alcohol consumed. Both methods may tend to under-estimate the true alcohol-HDL-C association.
{"title":"Alcohol intake and high density lipoprotein-cholesterol: comparison of food frequency questionnaire and diet record in a general population sample.","authors":"E. Müller, T. Stürmer, H. Brenner","doi":"10.1080/135952201317080409","DOIUrl":"https://doi.org/10.1080/135952201317080409","url":null,"abstract":"BACKGROUND\u0000Moderate alcohol consumption is known to affect several cardiovascular risk factors, including high density lipoprotein-cholesterol (HDL-C). Accurate measurement of alcohol intake in epidemiological studies is crucial for valid estimation of alcohol-related effects.\u0000\u0000\u0000METHODS\u0000We compared two widely used alcohol-intake assessment methods, a food frequency questionnaire (FFQ) and a 7-day diet record (DR) regarding the association between alcohol intake and HDL-C in the general population.\u0000\u0000\u0000RESULTS\u0000In a representative sample (842 men, 1103 women) of the population of former West Germany (VERA study), 75.6% of the participants reported drinking alcoholic beverages in the FFQ, whereas the percentage was 84.9% according to the DR. The median daily alcohol intake of consumers was 10.3 and 12.1 g, as assessed by the FFQ and the DR, respectively. There was moderate agreement between reported consumption levels ranked by quintiles according to FFQ and DR (kappa = 0.49). With both approaches alcohol intake showed a strong positive association with HDL-C in linear regression models. The estimated increases in HDL-C (mg dL(-1)) per gram alcohol per day from the FFQ and DR were 0.15 [95% confidence interval (CI): 0.12-0.18] and 0.14 (95% CI: 0.11-0.17), respectively. When participants with different classification of the amount of alcohol consumed by FFQ and DR were excluded from the analysis, the association between alcohol intake and HDL-C was more pronounced.\u0000\u0000\u0000DISCUSSION\u0000Our analyses suggest that both FFQ and DR lead to similar results regarding the alcohol-HDL-C association in the general population, despite major differences in the recorded prevalence of drinking and amount of alcohol consumed. Both methods may tend to under-estimate the true alcohol-HDL-C association.","PeriodicalId":80024,"journal":{"name":"Journal of epidemiology and biostatistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59835071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-09-01DOI: 10.1080/135952201753336852
L. Bisanti, A. Russo
{"title":"Development of a protocol for evaluation of mammographic surveillance services in women under 50 with a family history of breast cancer by J Mackay...","authors":"L. Bisanti, A. Russo","doi":"10.1080/135952201753336852","DOIUrl":"https://doi.org/10.1080/135952201753336852","url":null,"abstract":"","PeriodicalId":80024,"journal":{"name":"Journal of epidemiology and biostatistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59836254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-09-01DOI: 10.1080/135952201753337022
J. Benichou
{"title":"Development of a protocol for evaluation of mammographic surveillance services in women under 50 with a family history of breast cancer by J Mackay...","authors":"J. Benichou","doi":"10.1080/135952201753337022","DOIUrl":"https://doi.org/10.1080/135952201753337022","url":null,"abstract":"","PeriodicalId":80024,"journal":{"name":"Journal of epidemiology and biostatistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59837011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-05-01DOI: 10.1080/135952201317080689
M. Law, G. Dore, J. Kaldor
{"title":"Projecting severe sequelae of injection-related hepatitis C virus epidemic in UK by SM Bird, DJ Goldberg and SJ Hutchinson","authors":"M. Law, G. Dore, J. Kaldor","doi":"10.1080/135952201317080689","DOIUrl":"https://doi.org/10.1080/135952201317080689","url":null,"abstract":"","PeriodicalId":80024,"journal":{"name":"Journal of epidemiology and biostatistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59835546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-01DOI: 10.1080/135952201753172962
A. Gould, C. Begg, Jam Mar
{"title":"Two cheers for P-values? by S Senn","authors":"A. Gould, C. Begg, Jam Mar","doi":"10.1080/135952201753172962","DOIUrl":"https://doi.org/10.1080/135952201753172962","url":null,"abstract":"","PeriodicalId":80024,"journal":{"name":"Journal of epidemiology and biostatistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59835793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-01-01DOI: 10.1080/135952201317225444
M. Hauptmann, K. Berhane, B. Langholz, J. Lubin
BACKGROUND Different approaches have been proposed to investigate latency in epidemiologic studies where detailed exposure histories are available. METHODS We demonstrate the application of a flexible, yet parsimonious, spline function model to investigate latency patterns for radon progeny exposure and lung cancer in the Colorado Plateau uranium miners cohort. The model extends a previously proposed bilinear model. RESULTS The excess relative risk (ERR) reached a maximum of 0.6 per 100 working level months, for exposures received 14 years previously. The ERR then declined, and was estimated to approach zero for exposures received 35 years and more in the past. The point-wise 95% confidence intervals supported ERRs > 0 for the period 9-32 years before the event. The estimated latency curve was homogeneous across categories of attained age, duration of exposure, rate of exposure, and smoking. CONCLUSIONS The proposed spline model is a flexible tool for latency analyses, and extends previously used methods.
{"title":"Using splines to analyse latency in the Colorado Plateau uranium miners cohort.","authors":"M. Hauptmann, K. Berhane, B. Langholz, J. Lubin","doi":"10.1080/135952201317225444","DOIUrl":"https://doi.org/10.1080/135952201317225444","url":null,"abstract":"BACKGROUND Different approaches have been proposed to investigate latency in epidemiologic studies where detailed exposure histories are available. METHODS We demonstrate the application of a flexible, yet parsimonious, spline function model to investigate latency patterns for radon progeny exposure and lung cancer in the Colorado Plateau uranium miners cohort. The model extends a previously proposed bilinear model. RESULTS The excess relative risk (ERR) reached a maximum of 0.6 per 100 working level months, for exposures received 14 years previously. The ERR then declined, and was estimated to approach zero for exposures received 35 years and more in the past. The point-wise 95% confidence intervals supported ERRs > 0 for the period 9-32 years before the event. The estimated latency curve was homogeneous across categories of attained age, duration of exposure, rate of exposure, and smoking. CONCLUSIONS The proposed spline model is a flexible tool for latency analyses, and extends previously used methods.","PeriodicalId":80024,"journal":{"name":"Journal of epidemiology and biostatistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59835449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-01-01DOI: 10.1080/135952201753172980
M. Mccredie, M. Staples, W. Johnson, D. English, G. Giles
BACKGROUND This study was devised to determine the prevalence of urinary symptoms among men living in the Australian cities of Melbourne, Sydney or Perth, and to identify factors associated with the presence of moderate-to-severe urinary symptoms. METHODS The study comprised a population-based sample of 1,216 men, aged 40-69 years, whose names were obtained through electoral rolls and who participated as controls in a case-control study of risk factors for prostate cancer. As part of a structured face-to-face interview, the men completed the International Prostate Symptom Score (IPSS). Men with moderate (IPSS = 8-19) or severe (IPSS > or = 20) urinary symptoms were compared with those with mild or no symptoms (IPSS < 8) using unconditional logistic regression. RESULTS The age-specific prevalence of moderate-to-severe urinary symptoms (IPSS > or = 8) in men aged 40-49, 50-59, 60-69 years was 16%, 23% and 28%, respectively. Compared with men with no or mild urinary symptoms (IPSS < 8), men with moderate-to-severe symptoms were more likely to report not currently living as married [odds ratio (OR) = 1.5; 95% confidence interval (CI) 1.1-2.0] and being circumcised (OR = 1.5; 95% Cl 1.2-2.0). The increased likelihood associated with drinking an average of > 60 g day(-1) of alcohol in the 2 years before interview was of marginal statistical significance (OR = 1.6; 1.0-2.6). There were no significant differences between men with IPSS > or = 8 and those with IPSS < 8 with respect to body mass index, education level, having had a vasectomy, or cigarette smoking. CONCLUSION Among Australian men, being circumcised, or not currently living as married, were associated with increased prevalence of urinary symptoms.
{"title":"Prevalence of urinary symptoms in urban Australian men aged 40-69.","authors":"M. Mccredie, M. Staples, W. Johnson, D. English, G. Giles","doi":"10.1080/135952201753172980","DOIUrl":"https://doi.org/10.1080/135952201753172980","url":null,"abstract":"BACKGROUND This study was devised to determine the prevalence of urinary symptoms among men living in the Australian cities of Melbourne, Sydney or Perth, and to identify factors associated with the presence of moderate-to-severe urinary symptoms. METHODS The study comprised a population-based sample of 1,216 men, aged 40-69 years, whose names were obtained through electoral rolls and who participated as controls in a case-control study of risk factors for prostate cancer. As part of a structured face-to-face interview, the men completed the International Prostate Symptom Score (IPSS). Men with moderate (IPSS = 8-19) or severe (IPSS > or = 20) urinary symptoms were compared with those with mild or no symptoms (IPSS < 8) using unconditional logistic regression. RESULTS The age-specific prevalence of moderate-to-severe urinary symptoms (IPSS > or = 8) in men aged 40-49, 50-59, 60-69 years was 16%, 23% and 28%, respectively. Compared with men with no or mild urinary symptoms (IPSS < 8), men with moderate-to-severe symptoms were more likely to report not currently living as married [odds ratio (OR) = 1.5; 95% confidence interval (CI) 1.1-2.0] and being circumcised (OR = 1.5; 95% Cl 1.2-2.0). The increased likelihood associated with drinking an average of > 60 g day(-1) of alcohol in the 2 years before interview was of marginal statistical significance (OR = 1.6; 1.0-2.6). There were no significant differences between men with IPSS > or = 8 and those with IPSS < 8 with respect to body mass index, education level, having had a vasectomy, or cigarette smoking. CONCLUSION Among Australian men, being circumcised, or not currently living as married, were associated with increased prevalence of urinary symptoms.","PeriodicalId":80024,"journal":{"name":"Journal of epidemiology and biostatistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59836278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-01-01DOI: 10.1080/135952201317080661
Sheila M. Bird, Goldberg Dj, Sharon J. Hutchinson
BACKGROUND Hepatitis C is transmitted by transfusion of unscreened blood, through injecting drugs, from mother-to-child and, on occasion, sexually. Transmission generally requires that the infector is hepatitis C virus (HCV) RNA positive, a 'carrier'. About three-quarters of injectors who are hepatitis C antibody positive are HCV-RNA positive and so infectious to others. Incubation periods from HCV infection to cirrhosis and hepatocellular carcinoma are even longer than from HIV infection to AIDS, being counted in decades; they depend on age, gender, alcohol consumption and co-infection with other viruses. We identify 25 data sources that are available, or required, for projecting the severe sequelae of the injection-related hepatitis C epidemic. DATA SOURCES Three data sources relate to hepatitis C diagnosis: register of confirmed HCV infections (with initial of first name + soundex of surname + date of birth + gender = master index, exposure category, year of starting to inject, and region); surveys of HCV test-uptake by injectors and others; documentation of pregnancy and its outcome in HCV-infected women (injectors and others). Four data sources relate to HCV prevalence and incidence among injectors and others: anonymous testing for HCV antibodies in blood or saliva (for sentinel groups ranging from new blood donors, pregnant women, patients awaiting kidney transplantation, non-injector prisoners, health-care workers, non-injector heterosexuals attending genitourinary medicine clinics; to injectors in the community, at drug treatment centres or in prison); historical data on HCV prevalence in injectors; HCV incidence studies in injectors; and uptake of harm reduction measures--frequency of sharing and methadone substitution--by injectors. Key reporting problems in HCV incidence studies, which inhibit checks on the convenient exponential assumption for time from start of injecting to hepatitis C infection, are discussed. Nine critical data sources are identified for monitoring the late sequelae of hepatitis C carriage, its investigation and treatment: linkage surveillance, for example by master index, to identify deaths, hospitalisations or cancer registrations among confirmed HCV infections; surveys of HCV status among patients who undergo liver biopsy, are newly diagnosed with cirrhosis or are newly diagnosed with liver cancer; surveys of liver-biopsy rate in HCV-infected injectors and others; uptake and outcome of interferon + ribavirin in the treatment of hepatitis C carriers; cohort studies of HCV progression; sample surveys of genotype in HCV-infected injectors, and others; acute hepatitis B infections and uptake of hepatitis B immunisation by injectors; liver transplantation in HCV-infected patients; and hepatitis C-status and other risk factors in deaths from cirrhosis or liver cancer, to determine whether they are HCV and injector-related. Finally, nine critical data sources are identified for quantitative understanding of the under
{"title":"Projecting severe sequelae of injection-related hepatitis C virus epidemic in the UK. Part 1: Critical hepatitis C and injector data.","authors":"Sheila M. Bird, Goldberg Dj, Sharon J. Hutchinson","doi":"10.1080/135952201317080661","DOIUrl":"https://doi.org/10.1080/135952201317080661","url":null,"abstract":"BACKGROUND Hepatitis C is transmitted by transfusion of unscreened blood, through injecting drugs, from mother-to-child and, on occasion, sexually. Transmission generally requires that the infector is hepatitis C virus (HCV) RNA positive, a 'carrier'. About three-quarters of injectors who are hepatitis C antibody positive are HCV-RNA positive and so infectious to others. Incubation periods from HCV infection to cirrhosis and hepatocellular carcinoma are even longer than from HIV infection to AIDS, being counted in decades; they depend on age, gender, alcohol consumption and co-infection with other viruses. We identify 25 data sources that are available, or required, for projecting the severe sequelae of the injection-related hepatitis C epidemic. DATA SOURCES Three data sources relate to hepatitis C diagnosis: register of confirmed HCV infections (with initial of first name + soundex of surname + date of birth + gender = master index, exposure category, year of starting to inject, and region); surveys of HCV test-uptake by injectors and others; documentation of pregnancy and its outcome in HCV-infected women (injectors and others). Four data sources relate to HCV prevalence and incidence among injectors and others: anonymous testing for HCV antibodies in blood or saliva (for sentinel groups ranging from new blood donors, pregnant women, patients awaiting kidney transplantation, non-injector prisoners, health-care workers, non-injector heterosexuals attending genitourinary medicine clinics; to injectors in the community, at drug treatment centres or in prison); historical data on HCV prevalence in injectors; HCV incidence studies in injectors; and uptake of harm reduction measures--frequency of sharing and methadone substitution--by injectors. Key reporting problems in HCV incidence studies, which inhibit checks on the convenient exponential assumption for time from start of injecting to hepatitis C infection, are discussed. Nine critical data sources are identified for monitoring the late sequelae of hepatitis C carriage, its investigation and treatment: linkage surveillance, for example by master index, to identify deaths, hospitalisations or cancer registrations among confirmed HCV infections; surveys of HCV status among patients who undergo liver biopsy, are newly diagnosed with cirrhosis or are newly diagnosed with liver cancer; surveys of liver-biopsy rate in HCV-infected injectors and others; uptake and outcome of interferon + ribavirin in the treatment of hepatitis C carriers; cohort studies of HCV progression; sample surveys of genotype in HCV-infected injectors, and others; acute hepatitis B infections and uptake of hepatitis B immunisation by injectors; liver transplantation in HCV-infected patients; and hepatitis C-status and other risk factors in deaths from cirrhosis or liver cancer, to determine whether they are HCV and injector-related. Finally, nine critical data sources are identified for quantitative understanding of the under","PeriodicalId":80024,"journal":{"name":"Journal of epidemiology and biostatistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59835173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-01-01DOI: 10.1080/135952201317225471
J-P Nakache, A. Guéguen, Jf Maillefert, M. Dougados
BACKGROUND A composite index would help in medical practice for considering total hip replacement (THR) in hip osteoarthritis. In association with other parameters, such as age or general status, this index could serve to objectively determine the time to THR surgery, and might be used as an outcome measure in therapeutic trials. The objective of this study was to propose such an index, taking into account symptomatic, structural and therapeutic variables, and impact on lifestyle. METHODS A curve-fitting procedure and a marginal model were used to highlight the average change in the variables over time. A discrete Cox model, with time-dependent covariates. was then performed to study the association between the variables and hip surgery, leading to the construction of a composite index. RESULTS The smoothing and fitting analysis suggested takes into account not only the variables, but also the changes in their values during the preceding year, when studying the association between variables and hip surgery. Five covariates were retained in the Cox model, among them only one concerns the changes during the preceding year, showing that the values of the covariates are more important that their changes during the preceding year for THR indication. The coefficients of the model were transformed into new coefficients, so that their sum provided a severity score with individual values 0-100. DISCUSSION Based on the values of reliable variables recorded during the four last visits, this score can be regarded as a valid index able to objectively help with THR indications. This score might also be used as an outcome measure in therapeutic trials.
{"title":"Use of longitudinal data analysis in the determination of a global score for total hip replacement indication in osteoarthritis patients.","authors":"J-P Nakache, A. Guéguen, Jf Maillefert, M. Dougados","doi":"10.1080/135952201317225471","DOIUrl":"https://doi.org/10.1080/135952201317225471","url":null,"abstract":"BACKGROUND A composite index would help in medical practice for considering total hip replacement (THR) in hip osteoarthritis. In association with other parameters, such as age or general status, this index could serve to objectively determine the time to THR surgery, and might be used as an outcome measure in therapeutic trials. The objective of this study was to propose such an index, taking into account symptomatic, structural and therapeutic variables, and impact on lifestyle. METHODS A curve-fitting procedure and a marginal model were used to highlight the average change in the variables over time. A discrete Cox model, with time-dependent covariates. was then performed to study the association between the variables and hip surgery, leading to the construction of a composite index. RESULTS The smoothing and fitting analysis suggested takes into account not only the variables, but also the changes in their values during the preceding year, when studying the association between variables and hip surgery. Five covariates were retained in the Cox model, among them only one concerns the changes during the preceding year, showing that the values of the covariates are more important that their changes during the preceding year for THR indication. The coefficients of the model were transformed into new coefficients, so that their sum provided a severity score with individual values 0-100. DISCUSSION Based on the values of reliable variables recorded during the four last visits, this score can be regarded as a valid index able to objectively help with THR indications. This score might also be used as an outcome measure in therapeutic trials.","PeriodicalId":80024,"journal":{"name":"Journal of epidemiology and biostatistics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59835715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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