Ectopic pregnancy          package:epicalc          R Documentation

_D_a_t_a_s_e_t _o_f _a _c_a_s_e-_c_o_n_t_r_o_l _s_t_u_d_y _l_o_o_k_i_n_g _a_t _h_i_s_t_o_r_y _o_f 
_a_b_o_r_t_i_o_n _a_s _a _r_i_s_k _f_a_c_t_o_r _f_o_r _e_c_t_o_p_i_c _p_r_e_g_n_a_n_c_y

_D_e_s_c_r_i_p_t_i_o_n:

     This case-control study has one case series and two control
     groups.
      The subjects were recruited based on three types of pregnancy
     outcome (outc)

_U_s_a_g_e:

     data(Ectopic)

_F_o_r_m_a_t:

     A data frame with 723 observations on the following 4 variables.

     '_i_d' a numeric vector

     '_o_u_t_c' a factor with levels 'EP' 'IA' 'Deli'

              EP    = ectopic pregnancy
              IA    = women coming for induced abortion
              Deli  = women admitted for full-term delivery

     '_h_i_a' a factor with levels 'never IA' 'ever IA'

     '_g_r_a_v_i' a factor with levels '1-2' '3-4' '>4'

_E_x_a_m_p_l_e_s:

     data(Ectopic)
     library(nnet)
     use(Ectopic)
     multi1 <- multinom(outc ~ hia + gravi)
     summary(multi1)
     mlogit.display(multi1)

     # Changing referent group of outcome
     ep <- outc == "EP"
     ia <- outc == "IA"
     deli <- outc == "Deli"
     multi2 <- multinom(cbind(ia, ep, deli) ~ hia + gravi)
     summary(multi2)
     mlogit.display(multi2)

