Table 3.

Correlation between PrEP adherence by DBS measured at current and immediately prior visits among TGW enrolled in the PrEParadas study, Rio de Janeiro, Brazil, 2017–2019

DBS level observed at visit “t–1”	DBS level observed at visit “t”			Total
	Low	Moderate	High
Low	86 (83.5%)	9 (8.7%)	8 (7.8%)	103
Moderate	20 (31.7%)	22 (34.9%)	21 (33.3%)	63
High	17 (6.4%)	32 (12.0%)	218 (81.6%)	267

Note: Low level: <350 fmol/punch, moderate: 350–699 fmol/punch and high: ≥700 fmol/punch. Table 3 shows the absolute and relative frequencies of DBS measure transitions from one visit to the following. These percentages estimate the transition probabilities Pr (Yit | Yit − 1) based on the correlation between PrEP adherence by DBS of each participant by visit pairs (i.e. a specific visit and its following visit). There are 433 transitions (or “pairs”) between the 563 observations since there is no participant's status before the first visit. Among participants with a low DSB level in the visit “t–1,” 83.5% maintained a low DBS level in the following visit (“t”). Among participants with a high DBS level in the visit “t–1,” 81.6% maintained a high DBS level in the next visit (“t”).

Abbreviations: DBS, dried blood spots; TGW, transgender women.