Table 3 Firth (penalized) regression analysis of risk factors for characteristics of local and imported malaria in patients attending selected health facilities in North-Western Province, Zambia, enrolled into the study

Species

 Constant

− 3.864

0.831

Inf

1

< 0.01

N/A

 Country (1 = Congo & Angola; 0 = Zambia)

3.664

1.067

14.7

1

< 0.01

39.0

5.9

445.9

 Test overall model evaluation

χ²

df

p

  Likelihood ratio test

14.7

1

< 0.01

  Wald test

11.8

1

< 0.01

Gametocytes

 Constant

− 3.339

0.648

Inf

1

< 0.01

N/A

 Country (1 = Congo & Angola; 0 = Zambia)

3.139

0.932

12.5

1

< 0.01

23.1

4.2

161.6

 Test overall model evaluation

χ²

df

p

  Likelihood ratio test

12.5

1

< 0.01

  Wald test

11.3

1

< 0.01