Table 2. Patterns of engagement defined for study.

Label	Pattern of engagement observed during months 0–6 after ART initiation	Pattern of engagement observed during months 7–12 after ART initiation
Continuous	No visit > 28 days late in first 6 months and next visit scheduled >6 months after initiation (i.e. all visits as planned or late ≤28 days)	Continuous or cyclical at 6 months* AND no visit > 28 days late in months 7–12 and next visit scheduled >12 months after initiation (i.e., all visits attended as planned or late ≤28 days)
Cyclical	Attended at least 1 visit late by more than 28 days between initiation and month 6 but subsequently re-engaged in care by 6 months after initiation.	Continuous or cyclical at 6 months*; attended at least one visit late by more than 28 days between months 7 and 12 but subsequently re-engaged in care by 12 months after initiation.
Immediate disengagement	No visits after date of ART initiation; not observed during months 0–6 after ART initiation	Not reported for months 7–12; aggregated under “Disengaged months 0–6”
Early disengagement	≥1 visit after date of ART initiation but last visit ≤ 3 months after initiation	Not reported for months 7–12; aggregated under “Disengaged months 0–6”
Late disengagement	≥1 visit after date of ART initiation but last observed visit occurs 4–6 months after initiation (i.e. no further scheduled or observed visits in 7–12 month period)	Not reported for months 7–12; aggregated under “Disengaged months 0–6”
Disengaged months 0–6	Composite pattern including all immediate, early, or late disengagers in first 6 months; no visits observed after 6 months	Classified as immediate, early, or late disengagers in first 6 months AND no visits observed during months 7–12
Disengaged months 7–12	Not reported for months 0–6	Classified as continuous or cyclical at 6 months; at least 1 visit observed in months 7–12 but ≥1 scheduled visit late by >28 days with no evidence of return during months 7–14
Transferred	Documented transfer to another healthcare facility during month 0–6	Documented transfer to another healthcare facility at any time from 0–12 months
Died	Death recorded at any time from 0–6 months	Death recorded at any time from 0–12 months

*To be classified as either continuous or cyclical during months 7–12 after ART initiation, clients have been observed to be cyclical or continuous by month 6 after ART initiation. Those who disengaged from care during months 0–6 cannot be classified as continuous or cyclical thereafter, by definition, as their last observed visit occurred during the first 6 months on ART.