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. 2021 Jul 2;74(6):957–964. doi: 10.1093/cid/ciab601

Table 2.

Crude Difference in Mean Number of Contacts Referred Comparing Individuals Diagnosed With Tuberculosis (“Index Participants”) With Different Characteristics

Index Participant Characteristica Incentive-based Household-based Crude Difference in Differencesb Comparing Mean Number of Contacts per Index Participant in Incentive-based vs Household-based Contact Investigation (95% Confidence Interval)c
Age, y
 <25 1.12 (0.33 to 1.91) 0.33 (–0.36 to 1.02) 0.79 (–0.16 to 1.75)
 25–44 0.38 (–0.17 to 0.92) 0.34 (–0.06 to 0.75) 0.03 (–0.65 to 0.71)
 ≥45 Reference Reference Reference
Female sex (vs male) 0.61 (0.09 to 1.13) 0.65 (0.28 to 1.02) –0.04 (–0.68 to 0.60)
Vhembe District (vs Waterberg District) 0.25 (–0.26 to 0.76) 0.84 (0.48 to 1.2) –0.59 (–1.22 to 0.04)
Living with HIV (vs not living with HIV) –0.30 (–0.83 to 0.23) 0.15 (–0.22 to 0.52) –0.45 (–1.09 to 0.20)
Mode of transport to clinic
 Private motorized Reference Reference Reference
 Public motorized 1.28 (0.19 to 2.37) 0.33 (–0.36 to 1.02) 0.96 (–0.34 to 2.25)
 Nonmotorized 0.99 (0.44 to 1.55) –0.54 (–0.91 to –0.16) 1.53 (0.86 to 2.20)
Travel time to clinic, minutes
 <30 Reference Reference Reference
 30–60 0.06 (–0.55 to 0.68) 0.28 (–0.12 to 0.69) –0.22 (–0.96 to 0.52)
 >60 0.37 (–0.28 to 1.03) 0.81 (0.36 to 1.27) –0.44 (–1.24 to 0.35)
Employment
 Regular work Reference Reference Reference
 Student/Irregular work 1.01 (0.21 to 1.81) 0.56 (–0.04 to 1.17) 0.45 (–0.55 to 1.45)
 Unemployed/Retired 0.71 (0.06 to 1.35) 0.51 (0.03 to 1.00) 0.20 (–0.61 to 1.00)
Number of tuberculosis symptomsd
 0 Reference Reference Reference
 1 0.93 (–0.17 to 2.04) 0.43 (–0.32 to 1.17) 0.51 (–0.83 to 1.84)
 2 0.30 (–0.73 to 1.32) 0.67 (–0.05 to 1.40) –0.38 (–1.63 to 0.88)
 3 0.83 (–0.19 to 1.85) 0.72 (0.02 to 1.41) 0.11 (–1.12 to 1.34)
 4 1.17 (0.17 to 2.17) 0.56 (–0.12 to 1.23) 0.61 (–0.59 to 1.81)
 ≥5 household members (vs <5 members) 0.85 (0.35 to 1.36) 2.24 (1.93 to 2.55) –1.39 (–1.98 to –0.80)

Abbreviation: HIV, human immunodeficiency virus.

aAll characteristics that we considered in the model were selected using lasso penalized regression and presented in this table.

bThese differences correspond to the crude differences shown in Figure 3.

cThe 95% confidence interval is based on robust covariance matrix estimation.

dTuberculosis symptoms include self-reported cough, fever, weight loss, and/or night sweats at the time of the interview.