The gold standard for demonstration of anti-fracture efficacy in osteoporosis trials is the primary, predetermined analysis of the intention to treat (ITT) population; this is highlighted by the requirement of fracture prevention efficacy in trials of at least 3 years' duration for registration of new therapies (FDA 1994; CPMP 2001).
We consider the large data sample of patients as a strength of this study, but to account for the variance in follow-up period of the patients we adjusted for the years of registration.
Given that belonging to a specific group did not modify the effect of remission variables, we analysed the two groups together, adjusting for year of registration, as well as for other confounders, in order to increase the power of our analyses.
We also created a graph for the number of registered physicians by year of registration for the years 1977 2006.
Incidence data for primary female breast cancer (ICD10=C50) for the Yorkshire RHA population were extracted from the NYCRIS database for all completed years of registration from 1982 to 1999 (35 739 cases).
The rates for the first years of registration are somewhat inflated by inclusion of prevalent cases of Parkinson's disease, as some of the patients might have had the disease for several years before the start of the National Hospital Register in 1977.
The controls were matched in gender, five-year age class and year of registration for suicide attempt.
Moreover, we assessed whether patients visited their GP during the year of registration for related complaints such as other cardiovascular diseases (K70 K90, excluding hypertension), and hypercholesterolemia and, for antidepressants, other psychological diagnoses in the ICPC-chapter P. The total number of other chronic diseases for which the patient contacted the GP in 2001 was also assessed.
The data were analysed by Kaplan-Meier survival analysis and by multiple Cox regression analysis, adjusted for year of registration, time period, sex, type of admission, Charlson comorbidity index, surgical operation, use of urinary tract catheter and time from admission to the prevalence survey date.
In the Netherlands it has been recommended that minimal values of semen quality of young (3 years old) stallions for registration in the studbook is a mean total number of progressive motile morphologically normal spermatozoa of 2 × 109 and a mean of 50% for motility and 50% of morphology of 2 ejaculates collected at one h interval [ 19].
