population surveys scopes, prevalence, incidence, health registries ettore beghi institute for...
TRANSCRIPT
Population Population SurveysSurveys
Scopes, Prevalence, Scopes, Prevalence, Incidence, Health Incidence, Health
RegistriesRegistriesEttore BeghiEttore Beghi
Institute for Institute for Pharmacological Research Pharmacological Research Mario Negri, Milano, ItalyMario Negri, Milano, Italy
SCOPE OF POPULATION SCOPE OF POPULATION SURVEYSSURVEYS
• Measure prevalenceMeasure prevalence• Measure incidenceMeasure incidence• Measure mortalityMeasure mortality• Identify cases for case-control studiesIdentify cases for case-control studies• Identify exposures for cohort studiesIdentify exposures for cohort studies• Study familial aggregation/geneticsStudy familial aggregation/genetics• Screen candidates for prevention/early Screen candidates for prevention/early
treatmenttreatment
ANATOMY OF A ANATOMY OF A POPULATION SURVEYPOPULATION SURVEY
• Definition of the study populationDefinition of the study population• Definition of diseaseDefinition of disease• Case ascertainment (prevalence, Case ascertainment (prevalence,
incidence and mortality)incidence and mortality)• Calculation of epidemiological indexesCalculation of epidemiological indexes• Distribution by time, place & person Distribution by time, place & person
DIAGRAM OF THE DIAGRAM OF THE IDENTIFICATION OF A DISEASE IDENTIFICATION OF A DISEASE IN THE GENERAL POPULATIONIN THE GENERAL POPULATION
Kurtzke, 1978Kurtzke, 1978
HOW TO DEFINE A HOW TO DEFINE A POPULATIONPOPULATION
• Geographic boundariesGeographic boundaries- Residency- Residency
- Istituzionalization - Istituzionalization - Migration- Migration
• Temporal boundariesTemporal boundaries- Prevalence period - Prevalence period
(point, (point, period, lifetime)period, lifetime)- Incidence period- Incidence period
MEASURES OF DISEASE MEASURES OF DISEASE FREQUENCYFREQUENCY
• INCIDENCEINCIDENCE: Number of individuals in a : Number of individuals in a population that become ill in a stated population that become ill in a stated period of timeperiod of time
• CUMULATIVE INCIDENCECUMULATIVE INCIDENCE: Proportion of : Proportion of a fixed population that becomes ill in a a fixed population that becomes ill in a stated period of timestated period of time
• PREVALENCEPREVALENCE: Proportion of a population : Proportion of a population affected by a disease at a given point of affected by a disease at a given point of timetime
• MORTALITYMORTALITY: Number of individuals in a : Number of individuals in a population died for a disease in a stated population died for a disease in a stated period of timeperiod of time
PREVALENCE AND PREVALENCE AND INCIDENCEINCIDENCE
MigratingMigratinginin
MigratingMigratingoutout
RecoveryRecoveryDeathDeath
IncidenceIncidence
PrevalenPrevalencece
Prevalence = Incidence Prevalence = Incidence x average durationx average duration
SOURCES OF NEUROLOGICAL SOURCES OF NEUROLOGICAL DISEASES IN DISEASES IN
EPIDEMIOLOGICAL STUDIES EPIDEMIOLOGICAL STUDIES • Hospital records• Ambulatory records• Electrophysiological (EMG) records• General practitioners’ files• Disability records• Lay associations• Tertiary centers• Death certificates• Diagnosis related groups (DRGs)• Disease registries
MIGRAINE IS A HETEROGENEOUS MIGRAINE IS A HETEROGENEOUS AND ILL-DEFINED CLINICAL AND ILL-DEFINED CLINICAL
CONDITIONCONDITION• Intensity, duration, frequency and
characteristics of attacks tend to vary in the general population
• In each patient, symptoms may vary with time
• Many individuals may have different types of headache
• Many individuals do not consult their doctor for headache
MIGRAINE WITHOUT MIGRAINE WITHOUT AURA (IHS, 1988)AURA (IHS, 1988)
• A. At least 5 attacks with criteria B-D• B. Attacks lasting 4-72 hr (no or poor treatment)• C. Headache with at least two features:
- Unilateral- Pulsating
- Moderate or severe• D. At least one among:
- Nausea and/or vomiting- Photophobia and/or
phonophobia• E. At least one of the following:
- Other disturbances excluded by hx and examination - Other disturbances excluded by diagnostic tests - Other disturbances, but migraine attacks verified
CHANGE IN THE PREVALENCE OF CHANGE IN THE PREVALENCE OF MIGRAINE WHEN VARYING THE MIGRAINE WHEN VARYING THE
NUMBER OF IHS DIAGNOSTIC CRITERIANUMBER OF IHS DIAGNOSTIC CRITERIA
0
5
10
15
20
25
Prevalence (%)
Moderate 2/4C,1/2DSevere 2/4C,1/2DModerate 3/4C,1/2DSevere 3/4C,1/2DModerate 2/4C,2/2DSevere 2/4C,2/2DModerate 3/4C,2/2DSevere 3/4C,2/2D
Merikangas et al, Merikangas et al, 19901990
EPILEPSY AND EPILEPSY AND EPILEPTIC EPILEPTIC SEIZURESSEIZURES
• EPILEPSYEPILEPSY = = Clinical condition characterized Clinical condition characterized by repeated unprovoked seizuresby repeated unprovoked seizures
• UNPROVOKED SEIZUREUNPROVOKED SEIZURE = = Seizure occurring Seizure occurring in the absence of known precipitants; it may in the absence of known precipitants; it may occur at the presence of a non-recent CNS occur at the presence of a non-recent CNS injuryinjury
• ACUTE SYMPTOMATIC SEIZURE ACUTE SYMPTOMATIC SEIZURE = Seizure = Seizure occurring in close temporal relationship with occurring in close temporal relationship with an acute CNS insultan acute CNS insult
EPILEPSY, ACTIVE & IN EPILEPSY, ACTIVE & IN REMISSIONREMISSIONDefinitionsDefinitions
• ACTIVE EPILEPSYACTIVE EPILEPSY:: epilepsy epilepsy currently being treated or whose currently being treated or whose most recent seizure has occurred most recent seizure has occurred (usually) within the past two to five (usually) within the past two to five years (years (Thurman et al, Epilepsia, Thurman et al, Epilepsia, 20112011) )
• EPILEPSY IN TERMINAL EPILEPSY IN TERMINAL REMISSIONREMISSION: absence of seizures for : absence of seizures for 2 or 5 years without AEDs 2 or 5 years without AEDs
ACUTE SYMPTOMATIC SEIZURESInterval from precipitating factor
CNS Insult Timing of occurrence
Stroke, head trauma, cerebral anoxia 1 week
Cerebral infection Positive clinical/laboratory findings
Brain abscess, cerebral tuberculoma During treatment
HIV infection Acute infection/metabolic disturb
Arterovenous malformation Acute hemorrhage
Multiple sclerosis Within 7 days of relapse
Autoimmune diseases Symptoms/signs of activation
Neurodegenerative disorders None identified
Epidemiology Task Force, Epilepsia Epidemiology Task Force, Epilepsia 20092009
EPIDEMIOLOGICAL INDEXES EPIDEMIOLOGICAL INDEXES OF EPILEPSY IN OF EPILEPSY IN
INDUSTRIALIZED COUNTRIESINDUSTRIALIZED COUNTRIES• IncidenceIncidence
EpilepsyEpilepsy 29-53 100,000/yr 29-53 100,000/yr Epilepsy+single seizuresEpilepsy+single seizures 73-8673-86
Acute sympt seizuresAcute sympt seizures 20-3020-30Status epilepticusStatus epilepticus 10-4010-40
• Cumulative incidenceCumulative incidence 1-3%1-3%• PrevalencePrevalence
Active epilepsyActive epilepsy 5-8 x1,0005-8 x1,000LifetimeLifetime 15-5015-50
• MortalityMortality 1-4 x100,000/yr 1-4 x100,000/yr • SMRSMR 2-32-3
DeCarli, Lancet DeCarli, Lancet NeurolNeurol2003: 2:152003: 2:15
PREVALENCE OF COGNITIVE IMPAIRMENT ACCORDING TO
CLINICAL DEFINITION
DeCarli, Lancet NeurolDeCarli, Lancet Neurol2003: 2:152003: 2:15
PROBLEMS REGARDING THE PROBLEMS REGARDING THE DIAGNOSIS OF DIAGNOSIS OF
POLYNEUROPATHYPOLYNEUROPATHY
• The majority of the available data comes from clinical series
• The diagnosis of polyneuropathy is based on clinical and elettrophysiological features
• Polyneuropathy includes a wide spectrum of disorders ranging from symptomatic clinical conditions to subclinical variants
• Diagnosis should be confirmed by a neurologist
Polyneuropathy in the Polyneuropathy in the ElderlyElderly
Principal SymptomsPrincipal Symptoms
• Muscle cramps• Restless legs syndrome• Burning feet• Muscle pain• Problems with handling objects• Impairment of standing and gait• ‘Glove’ and ‘stocking’ paresthesiae
POLYNEUROPATHY IN THE POLYNEUROPATHY IN THE ELDERLYELDERLY
Validity of the screening Validity of the screening questionsquestions
Monticelli et al, Neuroepidemiology Monticelli et al, Neuroepidemiology 19931993
POLYNEUROPATHY IN THE POLYNEUROPATHY IN THE ELDERLYELDERLY
Inter-rater agreement (kappa Inter-rater agreement (kappa statistic)statistic)
Monticelli et al, Neuroepidemiology Monticelli et al, Neuroepidemiology 19931993
EL ESCORIAL CRITERIA EL ESCORIAL CRITERIA FOR THE DIAGNOSIS OF FOR THE DIAGNOSIS OF
ALSALS• Based on the topographical location of upper
(UMN) and lower motor neuron (LMN) signs in 4 CNS regions, progression of these signs, and absence of other diseases
• Degree of diagnostic certainty (definite, probable, possible, suspected ALS) based on a different combination of UMN and LMN signs
Brooks, 1994Brooks, 1994
EL ESCORIAL CRITERIA FOR THE DIAGNOSIS OF
ALS• DEFINITE ALS
- LMN and UMN signs in 3 spinal regions - LMN and UMN signs in the bulbar region
and in 2 spinal regions• PROBABLE ALS
- LMN and UMN signs in 2 spinal regions• POSSIBLE ALS
- LMN and UMN signs in 1 region- UMN signs in 2 or more regions
- LMN signs rostral to UMN signs
• SUSPECTED ALS- LMN signs in 2 or more regions
Source: J NeurolSource: J NeurolSci 1994; 124 Sci 1994; 124 (suppl): 96-107(suppl): 96-107
DISEASE REGISTRIES
• Lists of diseases (or disease groups) in well-defined populations
• Collection of data on disease burden and identification of patients’ cohorts to be followed for specific purposes
• For rare diseases, registries represent a (re)source for the collection of sizable numbers of cases for focused studies
EXPLANATIONS FOR HIGHER AND MORE HOMOGENEOUS
RATES IN EUROPEAN REGISTRIES
• Prospective inception of cases• Multiple sources• Fairly complete case
ascertainment• Continuous surveillance• Use of the same diagnostic criteria
OBJECTIVES OF A POPULATION-BASED
REGISTRY
• Incidence and prevalence of the target condition• Temporal and geographic trends of the disease• Full clinical spectrum of the disease• Clinical and paraclinical markers of the disease• Practical management and socio-economic
implications of the disease• Data banks for clinical/biological material
PREREQUISITES FOR THE START OF A
REGISTRY
• Definition of the population at risk• Selection of the best source(s) of
cases• Choice of the correct diagnostic
criteria
SOURCES OF CASES• Hospital records• Outpatient records• Neurophysiology units’ archives• General practitioners’ files• Disability records• Lay associations’ files• ALS centers• Death certificates• Administrative files (hospital discharge
diagnoses)
THE EURALS CONSORTIUM IrelandIreland
5.0M5.0M ScotlandScotland
5.0M5.0M Lancashire & CumbriaLancashire & Cumbria
1.8M1.8M LondonLondon
2.8M2.8M Italy (all)Italy (all)
8.0M8.0M BelgradeBelgrade
2.0M2.0M MadridMadrid
1.0M1.0M LimousinLimousin
0.7M0.7M GermanyGermany ?? RussiaRussia ?? IsraelIsrael ??
Total Total >25M>25M
PRACTICAL RECOMMENDATIONS TO START A POPULATION-BASED
REGISTRY• Select a well-defined geographic area• Identify one or more accessible sources• Use valid and reliable diagnostic criteria• Set a network of specialists able to trace all
cases residing in the area• Select a number of core variables to verify
the correctness of the diagnosis and define the general profile of the disease
• Start specific studies only after preparing ad-hoc protocols and case collection forms