Table 1

Baseline values of input parameters used in models (Epidemiology parameters and costs (US$))
Parameters Screening with diet intervention Screening with exercise intervention Screening with duo-intervention Screening alone Control References
Epidemiology parameters
 Negative rate of 2-h PG¢ 0.96 0.96 0.96 0.96 [30]
 Positive rate of OGTT£ 0.305 0.305 0.305 0.305 [30]
 Proportion of Diagnosed IGT¤ 0.478 0.478 0.478 0.478 [30]
 Normal PG to IGT§ 0.0128 0.0128 0.0128 0.0128 0.0128 [30,31]
 IGT to onset of diabetes
  Initiation age of 25 0.0290 0.0273 0.0275 0.0400 0.0644 [12,32,33]
  Initiation age of 40 0.0754 0.0710 0.0716 0.104 0.1670 [12,32]
  Initiation age of 60 0.2320 0.2184 0.2200 0.3600 0.5778 [12,32,33]
 IGT to normal PGß 0.116 0.116 0.116 0.116 0.116 [34]
 Onset of diabetes to CVDð1 0.062 0.062 0.062 0.0675 0.0675 [35,36]
 Onset of diabetes to Nephropathyð2 0.001 0.001 0.001 0.001 0.001 [35,36]
 Onset of diabetes to Neuropathyð3 0.0043 0.0043 0.0043 0.005 0.005 [35,36]
 Onset of diabetes to Retinopathyð4 0.0046 0.0046 0.0046 0.0081 0.0081 [35,36]
 CVD to death&1 0.0058 0.0058 0.0058 0.0087 0.0087 [35,36]
 Nephropathy to death&2 0.0008 0.0008 0.0008 0.0003 0.0003 [35,36]
Costs (US$)a
 Cost for screening 3 3 3 3 [37]
 Diet or exercise intervention 362 362 [38]
 Duo-intervention 371 [38]
 Onset of diabetes 897 897 897 897 897 [5]
 CVD treatment 2078 2078 2078 2078 2078 [5]
 Nephropathy treatment 1089 1089 1089 1089 1089 [5]
 Neuropathy treatment 1324 1324 1324 1324 1324 [5]
 Retinopathy treatment 888 888 888 888 888 [5]

The hybrid tree combined a decision tree and Markov models. The decision tree consisted of five main arms representing five scenarios. The first three scenarios involved screening for undiagnosed diabetes and IGT followed by any of the three active lifestyle interventions (diet, exercise, and duo-intervention), which were applied to the IGT subjects. The fourth scenario involved screening for undiagnosed diabetes and IGT, but without formal interventions (physicians dispensed information brochures only), and the fifth scenario involved control group with no screening or intervention. ‘OGTT’ means oral glucose tolerance test. ‘IGT’ means impaired glucose tolerance. ‘PG’ means plasma glucose. ‘CVD’ means cardiovascular disease. Costs(US$)a involved following costs: unit costs of one-off screening (test of 2-hour PG after breakfast, a confirmatory OGTT), and were derived from the national standard prices of medicines in China; costs of lifestyle interventions (diet or exercise intervention, and duo-intervention) were the average annual costs and obtained from a domestic community-based trial in China[38]; treatment costs of diabetes-related disorders were derived from a study of treatment costs for diabetes in China [5]. The transition parameters were numbered corresponding to the transition paths in Figure 1. (#The complement probabilities of one branch. *The life-table information which was used to model competing causes of death. @The proportion of individuals with normal PG. ¢, £, ¤ Transition parameters which determined whether a subject would receive interventions. §, ¶, ð,&: Transition parameters used in the Markov models, among these, ð1 to ð4 determined four transitions from onset of diabetes state to different complications states (cardiovascular disease, retinopathy, nephropathy and overt neuropathy) respectively; &1 and &2 determined two transitions from CVD or nephropathy state to death state. We did not consider the neuropathy-specific and retinopathy-specific mortalities, since these complications are not fatal).

Liu et al.

Liu et al. BMC Public Health 2013 13:729   doi:10.1186/1471-2458-13-729

Open Data