Artichoke of Population Studies Clinical Practice. Part II

Outline of presentation 1) 2) 3) 4) 5) 6) Key messages HFA Thoughtful physicians: Difficult Questions EBM Measurement Iterative Loop COPCORD / WHO / ILAR Studies 7) In conclusion …… The cyclic process of differential diagnosis •Listen •Listen •Listen listen & generate hypotheses cross examine to gather data for hypothesis testing test hypotheses is one of the hypotheses valid? YES NO TAKE ACTION How do I select the appropriate diagnostic test? 1) 2) Diagnostic tests RARELY reveal a patient’s true state with certainty. Test selection should be restricted to those diagnostic tests whose results could change physician’s mind as to what should be done for a patient. Physicians often start treatment despite uncertainty about true state of patient. 3) Number of diagnostic hypotheses remaining during The steps of evaluating a symptom 15 10 5 0 chief complaint Number of diagnoses to be considered history physical exam tests Certain not to occur Equal chance of occurring or not occurring Certain to occur 0 0.5 1.0 Probability of disease - 1 Prior Probability Posterior Probability 0 0.5 1.0 Probability of disease - 2 P[disease] = 0.06 0 0.5 1.0 Probability of disease - 3 1) Convert information needs into answerable questions EBM: Essential Steps & Flowchart 2) Track down, with maximum efficiency, the best evidence with which to answer them (from the clinical examination, the diagnostic laboratory, the published literature, or other sources) 3) Critically appraise that evidence performance for its validity (closeness to the truth) & usefulness (clinical applicability) 4) Apply the results of this appraisal in clinical practice 5) Evaluate performance Clinical knowledge, experience, skills, guts, flair Patient Preferences Best Evidence Diagnosis, Therapy, Prognosis Performance Fig : Flowchart of evidence-based medicine (adapted from Jenicek7) Clinical aphorisms 1) 2) If you hear hoofbeats, think of horses, not zebras Rare manifestations of common diseases are often more likely than common manifestations of rare diseases If a test is unlikely to change the management of the patient, don’t do the test If a test result surprises you, repeat the test before taking action The first priority in differential diagnosis is to think about the diseases you can’t afford to miss 3) 4) 5) Outline of presentation 1) 2) Key messages HFA 3) 4) Thoughtful physicians: Difficult Questions EBM 5) 6) 7) Measurement Iterative Loop COPCORD / WHO / ILAR Studies In conclusion …… Measurement Iterative Loop Burden of Illness (Assessment) Monitoring & Reassessment Synthesis & Implementation of Program Prognosis Diagnosis Etiology or Causation Therapy Community Effectiveness Policy Process Efficiency Relevance of population based studies * Prevalence * Incidence * Risk factors * Protective factors * Knowledge, Attitude, Practice & Behavior Relevance of population based studies - 1 Prevalence = No. of affected persons present in the population at a specific time --------------------------------------------No. of persons in the population at that time Implication : - Useful measure of burden of disease - Age/gender prevalence - Valuable for planning health services & allocating resources (M) - Spectrum of disease seen (mild /moderate /severe) Relevance of population based studies - 2 Incidence : No. of new cases that occur during a specific period of time ----------------------------------------population at risk of developing the disease Implication : Helpful in exploring the relationship of an exposure & the risk of disease e.g. sore throat & RF Rheumatic fever – “licks the joint and bites the heart” Relevance of population based studies - 3 Risk factors : Factors associated with occurrence of disease – most likely to be present prior to the onset of disease Implication : Risk factors – potential causal implications eg. Hypertension & heart disease Relevance of population based studies - 4 Protective factors : Those which appear to have an inverse association with the presence or development of disease Implication : For potential treatment or even prevention of disorders eg. Low fat diet & atherosclerosis Relevance of population based studies - 5 Knowledge, Attitude, Practice, & Behavior (KAPB) Studies: Assess the knowledge, attitude, practice & behavior of a particular disease in the population Implication: - Health behavior - Treatment seeking behavior - Compliance of treatment Outline of presentation 1) 2) 3) 4) 5) 6) Key messages HFA Thoughtful physicians: Difficult Questions EBM Measurement Iterative Loop COPCORD / WHO / ILAR Studies In conclusion …… 7) - The Bhigwan (India) COPCORD : Methodology & First Information Report A Chopra, J Patil, V Billampelly, J Relwani, HS Tandale APLAR Journal of Rheumatoloty, September 1997 The Bhigwan (India) COPCORD Study: Publications - Prevalence of Rheumatic diseases in a Rural Population in Western India: A WHO-ILAR COPCORD Study A Chopra, J Patil, V Billampelly, J Relwani, HS Tandale J Assoc Physicians India, February 2001 - Pain & disability, perceptions & beliefs of a Rural Indian Population : A WHO-ILAR COPCORD study A Chopra, M Saluja, J Patil, HS Tandale The Journal of Rheumatology, 2002 The Bhigwan (India) COPCORD : Methodology & First Information Report - 1 Study objective : Well stated Study population : Characteristics well defined & compared with national level (generalizability) Study team : COPCORD team & good representation of local resources (manpower) Study design : Cross-sectional community based study Chopra et al. APLAR Journal of Rheumatology September 1997 The Bhigwan (India) COPCORD : Methodology & First Information Report - 2 Study instruments : Standardized COPCORD questionnaires - Questions translated to local language - Validated on 50 referral patients (General population) Chopra et al. APLAR Journal of Rheumatology September 1997 The Bhigwan (India) COPCORD : Methodology & first information report - 3 Survey teams : Trained Community Health Workers COPCORD Medical Team : One rheumatologist, one orthopedic surgeons, one rural doctor, two rheumatology research associates Data collection : House to house daily visits Daily operations were supervised Due care was taken to look at the NON respondents Results well presented Chopra et al. APLAR Journal of Rheumatology September 1997 Prevalence of Rheumatic diseases in a Rural Population in Western India: A WHO-ILAR COPCORD Study - 1 - Prevalence data from 1st rural Indian COPCORD survey in Bhigwan - Cross-sectional survey : n = 6034 - Significant rural spectrum of rheumaticmusculoskeletal symptoms/diseases (RMSD) Chopra et al. JAPI 2001 Prevalence of Rheumatic diseases in a Rural Population in Western India: A WHO-ILAR COPCORD Study - 2 Conditions Rheumatoid arthritis Prevalence 0.5 % (95% CI 0.3-0.7) 5.8% 0.9% 3.2% 2.3 % Remarks Highest ever reported from an Asian Rural COPCORD study - Osteoarthritis Inflammatory arthritis Soft tissue rheumatism – general Soft tissue rheumatism regional Chopra et al. JAPI 2001 Pain & disability, perceptions & beliefs of a Rural Indian Population : A WHO-ILAR COPCORD study - < 25% of patients perceive that they have severe problem which influences their work ability & personal life - 21% did not perceive a need to see a doctor Implications : - Health seeking behavior - Treatment & Compliance - Cost & quality of life implications Chopra et al. The Journal of Rheumatology 2002 Outline of presentation 1) 2) 3) 4) 5) 6) Key messages HFA Thoughtful physicians: Difficult Questions EBM Measurement Iterative Loop COPCORD / WHO / ILAR Studies 7) In conclusion …… Measurement Iterative Loop Burden of Illness (Assessment) Monitoring & Reassessment Synthesis & Implementation of Program Prognosis Diagnosis Etiology or Causation Therapy Community Effectiveness Policy Process Efficiency Relationship between incidence & prevalence Incidence Prevalence Recovery Death In conclusion ….. 1) 2) 3) 4) Key messages HFA Thoughtful physicians: Difficult Questions EBM 5) 6) Measurement Iterative Loop COPCORD / WHO / ILAR Studies 7) In conclusion …… Inferior doctors treated the patient’s disease, Mediocre doctors treat the patient as a person, Superior doctors treat the community as a whole. - Huang Lee, 2600 BC