Reframing clinical research frameworks: Case for a shift from a biomedical to a biopsychosocial one

The biomedical or reductionist approach

The reductionist model of healthcare has been in vogue for the past hundred years.⁵ The reductionist model, borrowed from the mechanical engineering world, categorises disease based on organ, tissue, cell and sub-cellular involvement, in a cause-effect model. Modern medicine underpinned in the reductionist system relies heavily on the battery of diagnostics available for disease diagnosis and therapy.¹ In the biomedical approach, the focus is on identifying the organs involved and the immediate cause–whether infective, inflammatory, degenerative, neoplastic, congenital, or combinations of the above. The reductionist model aims at therapy based on fixing the diseased part, and not as much in the upstream factors and other non-medical ones that contribute to disease.

Biopsychosocial (BPS) model

The biopsychosocial model of health and illness as proposed by Engel (1977) implies that behaviour, thought, and feeling may influence a physical state.⁶ He disputed the long-held assumption that only the biological factors of health and disease are worthy of study and practice. He argued that psychological and social factors influence biological functioning and play a role in health and illness⁶ (Fig. 2). Engel based his arguments on Ludwig von Bertalanffy ‘General Systems theory’ which proposed an interdisciplinary framework for understanding systems as a whole, focusing on the relationships and interactions between their components rather than just the individual parts. The BPS looks beyond the organs to the upstream factors determining disease and health. This holism helps define disease and health states better.⁷

Close

Fig. 2.

Biopsychosocial framework for health and disease (Source: Created using http://www.freepik.com>Designed by pikisuperstar/Freepik</a>).

Export to PPT

The BPS model is particularly relevant to non-communicable diseases (NCDs) like diabetes, hypertension, cardiovascular diseases, and cancer which result from a complex interplay between biological, genetic, social, behavioural and psychological factors.⁸ Pathways to a number of NCDs like diabetes, hypertension, and coronary heart disease are shared with obesity, lack of physical activity and poor dietary habits being common drivers for the same. The BPS framework is also more aligned to the concept of ‘health and wellbeing’ as defined by World Health Organization.

Models in the context of clinical research

The structure of evidence-based treatment is predominantly driven by clinical trials. Randomised controlled trials (RCTs) are considered higher in the hierarchy of evidence generation.⁹ Most RCTs do not take account the non-medical determinants of health, despite adequate evidence suggestive of the same.¹⁰

Typically, in clinical research biomedical patient characteristics including demographic, anthropometric, risk-factors, laboratory parameters alongside the therapy, are profiled while comparing outcome measures between the intervention and control arms in a RCT or cases and controls in observational studies.

To our view, therein lies an inherent bias. For example, a study participant in a clinical trial with poor access to healthcare would have worse outcomes as compared with a participant with better access. The same would hold good for lower socioeconomic and educational status, environmental pollution, compliance to drugs and a healthy lifestyle, and mental stress levels as well.¹¹ Factoring for the biomedical determinants, ignoring the non-medical determinants has serious limitations.

Targeted organ and tissue specific diagnostics in the biomedical approach narrows the therapeutic approach to tissue and organs disregarding the non-medical determinants. The macro-environment that leads to the cellular, molecular, or organ involvement needs to be understood better alongside the contributors and constituents to that environment. This is well exemplified by multimorbidity–an increasingly common condition in older adults, –defined as presence of two or more chronic conditions. The cellular or molecular basis for the disparate conditions may be different while sharing the common contributory macro-environment pathway which have led to the multimorbid state. This calls for a more customised approach to the disease condition and its determinants rather than for a reductionist one.¹²

The pros and cons of reductionist medical care

The advantages of the present system include the ease of quantification, as numbers convey meaning even to the less literate and enable the quantification of benefits or harms through representative data. The cellular and micro-cellular basis for diseases as studied through proteomics, metabolomics, and transcriptomics help in understanding the molecular assembly for disease processes and possible pathways of prevention. Assimilation of physical and biochemical principles into medical uses has resulted in-better imaging and diagnostic modalities for diseases (CT scans, magnetic resonance etc.). Practice of evidence-based medicine ensures guideline based medical therapy that brings uniformity in treatment to a particular disease condition (Table).

Advantages of the biopsychosocial approach

Plants and animals thrive in certain ecosystems or biomes and the same could apply to humans as well. Humans are molded as much by the environment in which they are born, live and work as by their genes. That birth weight, age of menarche and menopause, gestational diabetes, and hypertension etc. all have a bearing on future non-communicable diseases.^11,13,14 An inclusive research design should factor for the social determinants, conventional risk factors, mental health, stress, hours of sleep, dietary habits, and compliance to therapy, all of which have a bearing on health.^15,16

Possible solution

Clinical research is largely modelled on the biomedical framework. Behavioral factors, environmental pollution, mental health, stress, and other non-medical determinants are factored for in contextual clinical research, while the biomedical parameters are factored in by default. The biopsychosocial (BPS) framework conforms to a model encompassing both the biomedical and non-medical determinants. It is thus logical that the BPS framework should be utilised for all clinical research, whether experimental or observational.

For more robust evidence generation from clinical research, social determinants of health and other non-medical determinants need be considered. Hippocrates advised that ‘whoever wishes to study medicine properly should consider the seasons of the year the hot and the cold…. the waters…. and the way that the inhabitants live…. whether they are fond of drinking and eating to excess and given to indolence, or are fond of exercise and labor.’ It is time to go back to the drawing board and redesign and redefine research and medical education, to make it more personalised, looking at the whole and not a part, considering that evidence generation and its application in clinical practice is an iterative process. The biopsychosocial model seems far more suited than the in-vogue, biomedical model.