BIOSTATISTICS

Fri, 09 Jun 2017 10:51:56 +0000

Introduction

This article is follow-up of the earlier article done early this year. It focuses on a branch of statistics known as biostatistics. I now present to you Biostatistics Part II since a number of people are not familiar with the field. This is dedicated to giving you some highlights about biostatistics using the public health platform as we continue our journey in The Word of Statistics.

The word biostatistics is a combination of two words i.e. bio and statistics. Bio means something that involves life or living organisms. Statistics is defined as the science that deals with collection, analysis and interpretation of data. Therefore, biostatistics is a science that deals with the collection, analysis and interpretation of living organisms [life] data. The living organisms can be human beings or animals. At higher education institutions it can be taken as a course in a programme or a complete programme on its own. Those that are trained in the field of biostatistics are referred to as biostaticians. These biostatisticians are popularly referred to as “data detectives who uncover patterns and clues [indications] through data description and exploration. They are also data judges who confirm and adjudicate decision using inferential methods” (Gerstman, 2008). This branch of statistics deals with techniques of making conclusions about the population. Inferential statistics builds upon descriptive statistics. The inferences are drawn from particular properties of sample to particular properties of population. These are the types of statistics most commonly found in research publications. They uncover patterns and clues by carrying out exploratory data analysis and descriptive statistics. This aspect of organisation, presentation and summarization of data are labelled as descriptive statistics. They judge and confirm clues by making generalisations and conclusions through the use of biostatistical inference.

Biostatistics focuses on quantification and explaining of some of the variation in the health and medical sciences. This implies application of statistical methods to the solution of health and medical problems. This article will focus on biostatistics on the platform of public health, which is defined as “the science and art of preventing disease, prolonging life and promoting health through the organised efforts and informed choices of society, organisations, public and private, communities and individuals.”

Uses of Biostatistics

There are many uses of biostatistics some of which are:

(a)        Using biostatistics, one can identify health trends that lead to life-saving measures through the application of statistical procedures, techniques, and methodology as demonstrated in the figure below. Forecasting scenarios, identifying health trends within the community, explaining biological phenomena, as well as determining the causes of disease and injury require biostatistics. It is, therefore, an integral part of public health. Biostatistics is usually used together with epidemiology. I usually refer to these as being ‘cousins’ as they are the major pillars of public health.

(b)       The data from the Zambia Demographic and Health Surveys (ZDHS) conducted between 1992 and 2014 gives an increase in contraceptive prevalence rates as part of trend analysis. You may wish to know that the ZDHS collects, analyses, and disseminates representative data on housing characteristics, marriage and sexual activity, fertility, family planning, infant and child mortality [deaths], malaria, HIV/AIDS, etc. on fertility rate, HIV, and nutrition. All these require biostatitical skills and knowledge. The ZDHS is conducted every five years by the Central Statistical Office (CSO) in partnership with the Ministry of Health.

(c)        Determining the health status of people using Body Mass Index (BMI) in order to estimate overweight and obesity. BMI is a tool that is commonly used to estimate overweight and obesity in children and adults.  Overweight and obesity ranges are measured by using weight and height to compute a person’s BMI. The BMI is used because, for most people, it correlates with the amount of fat in their bodies. For example, if as an adult your height is 1.67 and weight is 72kg then your BMI is 70/(1.68)2 = 24.8. This is classified as normal weight. If another person has a height of 1.65 and weight of 75kg, the BMI = 27.5 categorised as overweight.

(d)       Biostatistics is used in conducting experiments on human subjects [clinical trials] in the design, data collection and analysis. There are stages that are involved in these trials and biostatisticians assist in collecting and analysing data from such trials for appropriate biostatistical conclusions to be made.

(e)        Measurements are taken at clinics and hospitals on patients such as weight, age, blood pressure, temperature etc. The data collected is analysed and appropriate decisions are made. These measurements form part of biostatistics.

(f)        One branch of descriptive statistics of special relevance in health is that of vital statistics i.e. birth, death, marriage, divorce, and the occurrence of particular disease. They are used to characterise the health status of a population. Coupled with results of periodic censuses and other special enumeration of populations, the data on vital events relate to an underlying population and yield descriptive measures such as birth rates, morbidity rates, mortality rates, life expectancies, and disease incidence and prevalence rates that pervade both medical and lay literature.

(g)        It is a fact that pharmaceuticals are an essential component of a quality health system. Biostatistics is used in essential pharmaceuticals and medical supplies. This is done by collecting data on the supply and consumption of these essential pharmaceuticals and medical supplies. By analysing the data health service providers are able to determine the most consumed ones and even determining the season of demand using biostatical descriptive tools.

(h)       The routine data sources of health information include: the HMIS, the Integrated Diseases Surveillance and Response (IDSR), the Human Resource Information System (HRIS), Drug and Logistics Management Information System (DLMIS) and the Financial and Administrative Management Information System (FAMS). However, the main source of routine health information is the facility based Health Management Information System (HMIS). Non Routine Sources of Health Information include population based and household surveys, antenatal sentinel surveillance as well as health systems assessments and surveys (including service provision assessments and health facility censuses). Among the key non-routine sources of health information are the Zambia Demographic and Health Survey (ZDHS), the Living Conditions Monitoring Survey (LCMS), the Zambia Sexual Behaviour Survey (ZSBS), the Malaria Indicator Survey (MIS). Other sources of information for health information include annual planning processes, joint annual reviews, performance assessments reviews and programme progress reports, the Health Facility Census (HFC), surveillance of causes of deaths, and the national census of population and housing.

(i)        From the National Health Strategic Plan 2011-2015, it was planned that some of the targets were:

• To increase access to integrated reproductive health and fam¬ily planning services and thereby, reduce Maternal Mortality Ratio (MMR) from 591 per 100,000 live births in 2007 to 159 by 2020.
• To reduce Maternal Mortality Ration (MMR) from 591 per 100000 live births in 2007 to 159 by 2015.
• To reduce Under-Five Mortality Rate (U5MR) from 119 per 1000 live births in 2007 to 63 by 2015.
• To halt and reduce the incidence of malaria from 252 per 1000 population in 2010, to 75 by 2015.
• To reduce Malaria Case Fatality Rate among children below the age of 5 years from 38 per 1000 in 2008 to 20 by 2015.

Biostatistics can be used to monitor progress in the achievement of these targets.

(j)         Biostatistics is used in determining health workforce for the country by determining the numbers of staff, distribution and also the skills mix for achieving quality health services provision to the Zambian people.

(k)      Methods of producing quantitative and qualitative summaries of information in public health: Tabulation and graphical presentations; Measures of central tendency, Measures of dispersion.

(l)        Biostatistics plays a key role in each of these functions. In assessment, the value of biostatistics lies in deciding what information to gather to identify health problems, in finding patterns in collected data, and in summarising and presenting these in an effort to best describe the target population. In so doing, it may be necessary to design general surveys of the population and its needs, to plan experiments to supplement these surveys, and to assist scientists in estimating the extent of health problems and associated risk factors.

(m)      Health service statistics comprise information on consultations by patients, services provided, and diagnoses. Health facilities routinely gather much of this information for local use, but it is rarely collected in standardized formats or reported to a national health database. Health service statistics are fundamental to managing public health services, identifying health trends, and allocating resources efficiently.

Conclusion

biostatistical methods enable the quantitative study of variation, and the summary, analysis and interpretation of data from studies that are subject to variability. The amount of variation and relative importance of different sources are often of interest. This is done by using biostatistical tools such as Analysis of Variance (ANOVA).

Using biostatistics, one can identify health trends that lead to life-saving measures through the application of statistical procedures, techniques, and methodology as demonstrated in the figure below. Forecasting scenarios, identifying health trends within the community, explaining biological phenomena, as well as determining the causes of disease and injury require use of biostatistics.