In some studies, the outcome of interest is the time until some event occurs: readmission to hospital, the next manic episode, or even death. Survival analysis is a technique which can be used to analyze such data. It has added usefulness because it allows us to use data from subjects who drop out of sight over the course of the follow-up period as well as from those who do not experience the event by the time the study ends. This article introduces this technique and provides some guidelines for designing follow-up trials.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.
[Show abstract][Hide abstract] ABSTRACT: To summarize the evidence on treatment withdrawal rates reported in observational studies and randomized controlled trials (RCTs) of methotrexate (MTX), parenteral gold (GST), sulphasalazine (SSZ) and hydroxychloroquine (HCQ) among patients with rheumatoid arthritis (RA).
Two independent Medline searches were used to retrieve relevant studies published between 1966 and 1997. Those which disclosed information on the number of patients withdrawing from the drug were retained. Cumulative probabilities of survival on treatment were then computed using actuarial survival estimates, and differences were tested using log-rank, Wilcoxon and Cox proportional hazards tests.
A total of 159 studies provided withdrawal information, and the numbers of patients who withdrew, in general or because of inefficacy or toxicity, could be abstracted from 110 studies contributing 142 treatment arms (MTX, 48; GST, 56; SSZ, 22; HCQ, 16). Data for HCQ were available only up to 24 months, but combined percentages of patients estimated to have continued MTX, GST or SSZ, respectively, for 60 months were 36, 23 and 22% when all failures were considered, 75, 73 and 53% when withdrawals due to lack of efficacy alone were considered, and 65, 36 and 48% when only withdrawals due to toxicity were taken into account. The Cox proportional hazards test performed on all withdrawals, after adjusting for year of publication and type of study, revealed that patients remained on MTX significantly longer than they did on the other three agents; however, the patients stayed significantly longer on GST than MTX when withdrawals for inefficacy were analysed separately. No significant differences in withdrawal rates were noted between observational studies and RCTs.
Patients with RA stay significantly longer on MTX than on other disease-modifying anti-rheumatic drugs. Higher withdrawal rates among those given GST are mainly due to high toxicity, whereas the majority of withdrawals from SSZ and HCQ result from lack of efficacy. Withdrawal rates in observational studies are similar to those reported in RCTs.
[Show abstract][Hide abstract] ABSTRACT: Twenty-six college women with a history of repeated childhood sexual abuse were recruited from the community and compared with 19 healthy female collegiate subjects on neurocognitive measures. Abused subjects showed increased response latency variability and diminished inhibitory capacity during a GO/NO-GO/STOP vigilance task. A strong association was found between duration of abuse and memory impairments. Math Scholastic Aptitude Test (SAT) scores were significantly lower in abused subjects when matched against comparison subjects and when compared to their own Verbal SAT scores. Childhood sexual abuse appears to be associated with a constellation of neuropsychological deficiencies even in a group of relatively healthy women.
Full-text · Article · Feb 2006 · Journal of Neuropsychiatry