This presentation is co-financed by the European Social Fund and the state budget of the Czech Republic

Spatial Statistics of Health Data: Case Study in Olomouc Region, Czech Republic

Lukáš MAREK

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Back to the History Naples Kingdom plague map

Filippo Arrieta - 1694

Map of yellow fever in New York Published by Valentine Seaman - 1798

Map of cholera outbreak in London John Snow - 1854

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Why Geographical Information Systems?

Advanced methods for spatial analyses

Spatial statistics

Exploration of spatial pattern

Visualization and presentation for non-geographers

(doctors, specialist)

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Spatial Analyses of Health Data - AOI Disease mapping

Visual description of spatial variability of the disease incidence Maps of incidence risk, identification of areas with high risk

Geographic correlation studies Analysis of associations among the incidence and

environmental factors Analyses of spatial pattern

Exploration of spatial and spatio-temporal patterns in data Disease clusters, randomness, …

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Data Collaboration with Regional Public Health Service in

Olomouc EPIDAT database

Mandatory records about infectious diseases and patients, manually fulfilled

Age, Sex, Date, Profession, Place of residence, infection, isolation, …

2002 – 2011 > 46 000 records Anonymized

Aggregation to the regular fishnet Hexagons with the size of average cadastral unit

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

EpiDat

Infection 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Sum

Salmonella 2197 1731 1522 1706 1261 803 700 594 515 352 11381

Viral Intestinal Infections 139 194 198 197 581 476 535 396 431 689 3836

Lyme Borreliosis 226 290 180 229 319 225 274 220 237 303 2503

Tick-Borne Encephalitis 16 34 33 28 58 32 24 46 38 54 363

Unspecified Viral Encephalitis 0 3 4 4 5 5 1 3 3 2 30

Viral Meningitis 12 12 15 31 16 26 16 29 25 20 202

Varicella 1930 2247 3341 2865 1973 3529 1904 3057 2623 2910 26379

Hepatitis A 5 11 11 12 6 6 152 66 49 50 368

Acute Hepatitis B 30 14 22 20 14 6 18 5 4 2 135

Parotitis 5 7 1 18 356 126 115 120 227 7 982

Sum 4560 4543 5327 5110 4589 5234 3739 4536 4152 4389 46179

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Software

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Choropleth mapping One of the most

common type of map Densities rather than

continuously distributed values

Visual tool for the analysis of spatial distribution of phenomenon

Relative values

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Identification of Spatial Processes Estimation of the nature of phenomenon Plenty of methods

Graphical Numerical

Testing of Complete Spatial Randomness Or other spatial processes

Scale dependency

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Graphical methods Morishita index plot

index of spatial aggregation for a spatial point pattern

Fry (Patterson) plot Scatterplot of the vector differences xj − xi between all pairs of

distinct points in the pattern

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Graphical methods Quadrat analysis

Quadrat count Visual evaluation

Quadrat test χ2 dispersion test of Complete

Spatial Randomness 506 tiles, χ2 = 11065.02, df = 505, p-

value < 2.2e-16

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Graphical methods Ripley‘s K-function

Reduced second moment function Mean number of points within distance from an arbitrary point Comparing (testing) to simulated CSR L-function

Scaled K-function

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Graphical methods Kernel density

Nonparametric statistical method for estimating the probability of a defined event

Intensity of the phenomenon in space Density map reveals the spatial clusters

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Global and Local Spatial „Clustering“ Exploring of the spatial autocorrelation More location based then attribute – position based Overview of global situation in entire area Moran‘s I, Getis Ord General G, …

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Local analyses E.g. LISA

Local indicators of spatial associations

Position of identified clusters Statistical significancy Intensity and type of clustering

Local Moran's I, Getis-Ord Gi*, Kuldorff‘s scan, Diggle‘s test, …

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Multivariate Clustering Similarity searching in

attribute space Classification of areas with

related properties of occuring diseases and their parameters

Classification of similar cases

Without spatial relations

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Problems / Challenges Geocoding Aggregation Neighbourhood estimation Modifiable areal unit problem Probability distribution of the disease occurrence Underlying processes Under / Overestimation of results leading to

misinterpretation Age / Population standardization

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Future work Spatio-temporal analysis Bayesian modelling and smoothing Multivariate statistics with spatial relations Neural networks for clustering GWR, GLMM

First InDOG Doctoral Conference, 29th October - 1st November 2012, Olomouc

Thank you for your attention