The global distribution of physicians and nurses

Aim: To explore the global distribution of physicians and nurses and the influence of gross national product per capita on this distribution, using available United Nations' (UN) sources. Objectives: to compare the international distribution of physicians and nurses by country; to examine the influence of gross national product per capita (GNP) on the global distribution of physicians and nurses; to explore the assumptions underlying the recommendations of The World Development Report 1993 Investing in Health for health workforce substitution; and to consider the implications for future studies of global health labour distribution. Design: A database was compiled from various UN sources on 147 countries. Using some of the variables from this database, a general linear regression model for log GNP per capita on each of the two dependent variables (log nurses and log physicians per 1000 population) was produced. Standardized residuals obtained from these bivariate regressions were calculated and plotted against each other to determine the relationship between the global distribution of physicians to population and that of nurses. From this analysis outlying countries could also be identified. Results: Ratios of physicians to population by country varied from 0.02 to 4.4 per 1000 population (or from 1 to 227 and 1-50,000 population), and nurses from 0.03 to 16.4 (or from 1 to 61 and 1-33,000 population). There was a positive correlation (r = 0.84, P < 0.001) between the number of physicians per 1000 population and the number of nurses per 1000 population. GNP explained 49% of the variation in physicians and 40% in nurses. Ranking of countries according to their standardized deviation from mean regression lines for GNP against health personnel in countries with both the lowest incomes and lowest numbers of health personnel, resulted in little change from the original rankings of ratios of physicians and nurses relative to population. For some of the wealthiest countries, there was a marked fall in global ranking and for some middle income countries a marked improvement in ranking. Conclusion: 70% of the distribution of nurses globally can be explained by the distribution of physicians, and the influence of GNP per capita on the global distribution of physicians and nurses appears to be substantial. In only a minority of the world's very poorest countries is there evidence to suggest that higher numbers of nurses substitute for low numbers of physicians. Standardization of the distributions by GNP demonstrates that many countries (but not the poorest) regress to within one standard deviation of the mean expected distribution. This suggests that countries could set optimum levels of physicians and nurses within the limits of their GNP. More realistically, the findings suggest that recommendations for modification of the structure of countries' health labour forces as a component of health care reform may be more difficult to achieve than at first appears. The potential unreliability of the data sources used, and the implications for the accuracy of the findings, are discussed.