To allow pre-index group comparisons and identification of selected comorbidities, control patients had a randomly assigned index date and were required to also have 6 months of continuous medical and prescription coverage preceding the index date.
A participant's exposure ended at the diagnosis or move out year (whichever was earlier) among cases and at a randomly assigned index year or move out year (whichever was earlier) among controls.
Controlling for a utilisation surge around first secure email use, we analysed difference of differences between propensity score-matched groups of secure patient clinician email users and non-users for utilisation 1 12 months before and 7 18 months after first email (users) or a randomly assigned index date (non-users).
Foremost, we consider a "signal" which exists at a frequency assigned to index 1.
This surface is a grid of rectangles where each rectangle is assigned an index i, a center position (x i, y i, z i ), an area A i, and a weight W i. Figure 1 depicts this grid.
RI involves the following two steps: First, instead of allocating one dimension in the multidimensional vector space to a single word, each word is assigned an "index vector" as its unique signature in the vector space.
For patients who had started an anticoagulant after their initial entry date, we assigned an index entry date that was the date of their first prescription of the anticoagulant during the study period.
The health state profile that it generates can be assigned an index score, often called a utility value, which represents preferences for that profile derived from a general population survey.
We randomly assigned an index date to the entire adult general population according to the distribution of index dates in donors.
Subsequently, warfarin non-users will be assigned an index date that corresponds to the length of time after the study start date to the index date for their randomly matched (on year of AF diagnosis) warfarin user.
During each experiment, we assigned an index u to each of the test persons.
