Why are emerging countries popular for clinical research?

BACKGROUND: The business of clinical research has changed in the past two decades, shifting from industrialised Western countries to so-called emerging markets such as Eastern Europe, Latin America and Africa. An appraisal of the trends could identify associated factors that may have implications for the local populations and their endemic diseases. OBJECTIVES: To identify potential reasons why emerging countries have become attractive places for international sponsors to conduct their clinical trials. METHODS: Using ClinicalTrials.gov, the Pan African Clinical Trials Registry, the National Health Research Database and the Nigeria Clinical Trials Registry, trend data on clinical research development were determined for two emerging African markets, Nigeria and South Africa (SA), from 2010 to 2018. Also, health data on the two countries from the fact sheets of health statistics of the World Health Organization were compared, as well as regulatory and ethical conditions. Available data were analysed using descriptive statistics and trend analysis. RESULTS: The impact of globalisation is evident from the upward trend in clinical trials in SA before 2010, and the clear downward trend thereafter. One reason for this change could be the alignment of SA's regulatory and ethical frameworks with the Western world. In contrast, the upward trend is only just beginning in Nigeria, with the introduction of ethical/regulatory frameworks, and supportive institutions making the business of clinical research more attractive on an international level. Although the number of international and local sponsors increased in Nigeria from 2010 to 2018, only the latter increased in SA, with the former decreasing over the same period. Overall, there is a mismatch between country-specific diseases and the drugs being tested, to the extent that leprosy, which is endemic in Nigeria, and tuberculosis in SA were not in the list of top 10 study areas in either country. CONCLUSIONS: The globalisation trend is evident in the clinical trials business, but cannot be generalised to all emerging countries. Timing and intensity vary from country to country relative to factors that advance the existing profit-orientated business models of the sponsors. Furthermore, various diseases have been localised, which entails a diversely increasing need for research.

Summarizing data through a piecewise linear growth curve model.

Most of the research in clinical trials is based on longitudinal designs, which involve repeated measurements of a variable of interest. Such designs are very powerful, both statistically and scientifically. Recent advances in statistical theory and software development incorporate the covariance structures such as unstructured, compound symmetry, auto-regressive and random effects, etc., for analysing longitudinal data. Hathaway et al. propose a technique for summarizing longitudinal data using linear growth curve model and establish that the number of summary statistics is fixed as four irrespective of the length of study. In this paper, we develop a procedure for analysing the longitudinal data through a piecewise linear growth curve model on the lines of Hathaway et al. Under different covariance structures, the linear model is fitted for Leprosy data and the residual sum of squares computed. Goodness of fit has also been considered for various models. In order to prove that the proposed method is robust and better than the others in terms of goodness of fit, simulation studies are carried out and the results presented.