Estimates of the national trend of drugs use during 2000-2030 in China: A population-based mathematical model.

BACKGROUND

The use of synthetic drugs has exceeded heroin to become a major public health concern in China. We aimed to estimate the trend of heroin-only, synthetic drug-only and poly-drug (heroin and synthetic drug) use during 2000-2030 period in China using existing data.

METHODS

We used data from the Annual Report on Drug Control in China and peer-reviewed publications. We constructed a mathematical model to estimate the drug use trend based on Monte Carlo simulations.

RESULTS

The best calibrated model estimated that the number of drug users would increase from 0.86 million to 3,120,059 (95% CI 2,669,214-3,570,904) during 2000-2030 period. The proportion of heroin-only users among the total drug users will decrease from 96.8% (95% CI, 96.6-97.1%) in 2000 to 36.9% (30.1-40.8%) in 2030, while the proportion of synthetic drug-only users will increase from 1.1% (0.9-1.3%) in 2000 to 57.7% (51.7-65.6%) in 2030. In contrast, the proportion of poly-drug users shared an increasing trend during 2000-2016 (from 2.1% (1.5-2.8%) to 15.1 (13.8-17.1%)) but declined to 5.5% (3.4-7.2%) in 2030. Estimated 46,370 (41,634-51,106) heroin-only users and 3767 (3481-4053) synthetic drug only users initiated poly-drug use in 2000. We observed a cross-over in 2012 where more synthetic drug-only users were initiating heroin use than heroin-only users initiating synthetic drug use. There will be estimated 2,094,052 (1,819,830-2,368,274) synthetic drug-only users and poly-drug users 211,407 (177,150-245,664) in 2030.

CONCLUSIONS

Synthetic drug use will become dominant in drug users in China, but poly-drug use of both heroin and synthetic drugs will remain substantial.