Table 2 Estimated association between covariates and hazards of injection cessation and relapse to injection among the people who inject drugs in Kerman and Tehran, Iran, 2018–2021

City

Tehran

1.50

1.09, 2.06

0.013

0.61

0.36, 1.05

0.074

Kerman

Ref

Ref

Age

1.00

0.98, 1.02

0.979

0.99

0.97, 1.01

0.588

Gender

Women

1.13

0.67, 1.88

0.647

1.56

1.01, 2.41

0.045

Men

Ref

Ref

Education

High school or above

1.06

0.75, 1.48

0.742

0.76

0.46, 1.14

0.165

Less than high school

Ref

Ref

Monthly income

≥ 100 USD

1.35

0.95, 1.91

0.095

1.62

1.02, 2.58

0.043

< 100 USD

Ref

Ref

Living with spouse or partner

Yes

1.27

0.78, 2.07

0.341

1.67

0.96, 2.89

0.067

No

Ref

Ref

Incarceration (L3M^*)

Yes

1.19

0.76, 1.87

0.434

0.71

0.30, 1.67

0.431

No

Ref

Ref

Length of injection career

≤ 1 years

1.42

0.82, 2.45

0.213

1.48

0.91, 2.40

0.112

2–5 years

1.21

0.76, 1.91

0.425

1.64

1.04, 2.59

0.034

> 5 years

Ref

Ref

Received free needles/syringes (L3M^*)

Yes

1.13

0.75, 1.68

0.553

0.75

0.44, 1.29

0.303

No

Ref

Ref

Receipt OAT (L3M^*)

Yes

0.91

0.63, 1.32

0.627

0.96

0.48, 1.89

0.903

No

Ref

Ref

Non-injection heroin use (L3M^c)

No

1.11

0.66, 1.87

0.674

0.79

0.33, 1.87

0.597

Yes

Ref

Ref

Non-injection methamphetamine use (L3M^c)

No

1.27

0.82, 1.98

0.285

1.14

0.60, 2.15

0.410

Yes

Ref

Ref

History of HIV test

Ever

0.90

0.60, 1.33

0.597

0.94

0.37, 2.43

0.905

Never

Ref

Ref

History of HCV test

Ever

0.97

0.57, 1.64

0.905

1.84

0.93, 3.63

0.079

Never

Ref

Ref