Application of log-linear models to pneumonia patients: a case study of Jigme Dorji Wangchuck National Referral Hospital (JDWNRH) in Bhutan

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1 Journa of Physics: Conference Series PAPER OPEN ACCESS Appication of og-inear modes to pneumonia patients: a case study of Jigme Dori Wangchuc Nationa Referra Hospita (JDWNRH in Bhutan To cite this artice: Sonam Zam and Montip Tiensuwan 018 J. Phys.: Conf. Ser Reated content - Appication of ogistic regression modes to cancer patients: a case study of data from Jigme Dori Wangchuc Nationa Referra Hospita (JDWNRH in Bhutan Choney Zangmo and Montip Tiensuwan - Time series anaysis of diabetes patients: A case study of Jigme Dori Wangchu Nationa Referra Hospita in Bhutan Thuten Singye and Suntaree Unhapipat - Ris factors for cardiovascuar diseases (CVDs patients in Bhutan Yeshi Dori and Montip Tiensuwan View the artice onine for updates and enhancements. This content was downoaded from IP address on 1/11/018 at 0:

2 ICAPM 018 IOP Pubishing IOP Conf. Series: Journa of Physics: Conf. Series ( doi : / /1039/1/01030 Appication of og-inear modes to pneumonia patients: a case study of Jigme Dori Wangchuc Nationa Referra Hospita (JDWNRH in Bhutan Sonam Zam and Montip Tiensuwan Department of Mathematics, Facuty of Science, Mahido University, Bango 10400, Thaiand Emai: moon7su@gmai.com Abstract: Pneumonia is a ung infection or sweing (infammation of the tissue in one or both ungs caused by bacteria Streptococcus pneumonia. Pneumonia caims the ives of the word s most vunerabe chidren. The aim of this study is to find the association between pneumonia variabes of pneumonia patients. The recorded data of 4190 JDWNRH pneumonia patients from 005 to 016 were used. A test of independence was conducted for a pneumonia patients and individua gender to identify the association between any two variabes using chi-square test and Cramer s V statistic. The variabes with maximum Cramer s V were formuated using two-dimensiona oginear modes to obtain estimate parameters, expected frequencies and standardized residuas. Three-dimensiona og-inear modes were appied to test the association among any three variabes. The anaysis of deviance is used to seect the best modes. The resut showed that most paired variabes were significanty reated at p-vaue ess than For a data, ward has a strong association with pneumonia types, age, status of ast contact and region. In addition, ength of stay has association with status of ast contact. 1. Introduction Googe defines pneumonia as a ung infection or sweing (infammation of the tissue in one or both ungs [1]. The bacteria Streptococcus pneumonia is one of the most common causes of pneumonia throughout the word. This bacterium was discovered by a French microbioogist Louis Pasteur and an American microbioogist George Sternberg in 1881 []. The second maor cause of pneumonia is the bacteria nown as Haemophius infuenza, discovered by Pfeiffer in 189 [3].The symptoms of pneumonia are cough, fever, sweating, shivering, oss of appetite, headache, nausea, oint and musce pain and a hard time breathing. For most peope, pneumonia can be treated at home. It often disappears in to 3 wees yet oder peope, babies, and peope with other diseases can become very i. They may need to be in the hospita. Some of the effective preventive measures are excusive breastfeeding for the first 6 months of ife, an effective and inexpensive way to treat chidhood pneumonia is through the use of antibiotics and vaccines, and using cean cooing stove. Therefore, the purpose of this study is to identify the associated factors among persona and cinica variabes of pneumonia patients using og-inear modes. Content from this wor may be used under the terms of the Creative Commons Attribution 3.0 icence. Any further distribution of this wor must maintain attribution to the author(s and the tite of the wor, ourna citation and DOI. Pubished under icence by IOP Pubishing Ltd 1

3 ICAPM 018 IOP Pubishing IOP Conf. Series: Journa of Physics: Conf. Series ( doi : / /1039/1/ Methodoogy.1Data coection In this study, recorded data of 4190 (33 maes and 1867 femaes of pneumonia patients from 005 to 016 were coected from Jigme Dori Wangchuc Nationa Referra Hospita (JDWNRH, Bhutan. JDWNRH is renowned across Bhutan for giving the most essentia heath management and assessment services. Not ony the hospita oos into the referred cases by 0 provinces hospita, but aso eeny serve non-referred cases from the neighboring cities and states with the best of its efforts. The data consisted of persona variabes and cinica variabes which are shown in Tabe 1. The persona data incudes three variabes: age, region and gender. The cinica data incudes five variabes: pneumonia type, ward, number of visits, ength of stay and status of ast contact. Tabe 1: Categories and eves of persona and cinica variabes incuded in the modes Category Divisions Persona Age (years 10, 11-0, 0 Gender Mae, Femae Region 1. Southern, Eastern, Western, Centra, Others. Southern, Eastern, Western, Others (ony for three-dimensiona og-inear modes of mae and femae Cinica Pneumonia type Pneumonia-unspecified organism, Others Ward 1. Pediatric, Medica, Others. Pediatric, Others (ony for three-dimensiona og-inear modes of mae and femae Hospita visits (days, Length of stay (days 15, 16-30, 30 Status of ast contact 1. Recovered, Death, Others. Recovered, Others (ony for three-dimensiona og-inear modes of mae and femae Some of the categories have more than one divisions, it is to reduce the vaue being ban or zero. From Tabe, the persona data show that more than 50 percent of the patients were mae and about 54 percent of the pneumonia patients were chidren aged 10 and beow. From cinica data, most of the patients were diagnosed with pneumonia-unspecified organism. Among wards, most of the patients were admitted in pediatric ward and east patients were admitted in eye and physica ward. About 98.7 percent of the patients visited hospita ess than or equas to two days with maority of the patients being admitted in the hospita for ess than or equas to 15 days. Status of ast contact tes us that with ess number of deaths, around 96.1 percent of the patients recovered from pneumonia.. Statistica Anaysis In this study, we carried out statistica anaysis in three stages. A test of independence was conducted to earn about the association between persona and cinica variabes, and among persona and cinica variabes incorporated with Cramer s V statistic. Cramer s V measures the strengths of association between two categorica variabes after chi-square has determined significance. The vaue ranges from 0

4 ICAPM 018 IOP Pubishing IOP Conf. Series: Journa of Physics: Conf. Series ( doi : / /1039/1/01030 to 1. A vaue cose to 0 indicates a wea association between variabes and cose to +1 shows a strong association. The Cramer s V can be obtained by V, (1 n (v 1 where is derived from chi-squared test, v is the smaer of the number of rows and coumns, and n is a sampe size. This statistic, Cramer s V can attain the maximum of 1 for tabes of any dimension. Tabe : Descriptive data for persona data and cinica data cassified by gender Variabes Mae Femae Tota Number % Number % Number % Persona data Age (years Region Southern Eastern Western Centra Others* Cinica data Pneumonia type Pneumonia, Unspecified organism Others** Ward Pediatric Medica Others*** Hospita visits Length of stay (days Status of ast contact Recovered Death Others**** Note: *such as India, China, Austraia & Bangadesh. **such as pneumonia due to infuenza virus, Streptococcus pneumonia, etc.***such as neonata, eye, etc.****such as absconded & referred out...1 Two-dimensiona og-inear modes The mode given is appied to study the association between any two variabes. The saturated or maxima mode is written as 3

5 ICAPM 018 IOP Pubishing IOP Conf. Series: Journa of Physics: Conf. Series ( doi : / /1039/1/01030 LogE Y, ( where is the grand average of the ogarithms of the expected frequencies,, are the main effects of the factors, and 1 1 J K JK. is the interaction effect of two factors with degrees of freedom J 1 1 ( K 1.. Three-dimensiona og-inear modes Lie Two-dimensiona modes, three-dimensiona modes are appied to study the association between any three variabes. The fu mode is given by LogEY (3 where is the grand average or overa mean,,, are the main effects of the factors,,, are the interaction effects of two factors, and is the interaction effects of three factors, with 1J 1K 1L1J 1K 1J 1L1K 1L1J 1K 1L1 JKL degrees of freedom...3 Goodness of fit Goodness of fit test is used to determine whether a og-inear mode used matches the rea sceneries. H 0 : The smaer mode fits the data we. H 1 : The arger mode fits the data we. Chi-squared statistic and og-ieihood ratio statistic are used to measure goodness of fit for contingency tabes as foowings: 1. Chi-square statistic is J K ( O E (4 1 1 E The test is to reect H 0 if, J1K1and accept H 0 otherwise, with an approximated significance eve, and degrees of freedom J 1K 1.. The og-ieihood ratio statistic or deviance is O G O og (5 E with J 1K 1 degrees of freedom. Thus, the test is to reect H 0 if D, J1K1 and accept H 0 otherwise. 3. Resuts and discussion In this section, we present the resuts from testing associations between two distinct pneumonia variabes for mae and femae patients using chi-square statistic and Cramer s V. Tabe 3 iustrates the summary of the reationship between the persona and cinica variabes which gave maximum Cramer s V for mae and femae pneumonia patients at p-vaue < Tabe 3 shows that ward and status of ast contact, ength of stay and status of ast contact, age and ward, and region and ward have strong association for both the genders. However, pneumonia type and ward had association ony for mae patients. It aso indicates that ward is having a strong reationship with persona variabes as we as cinica variabes. 4

6 ICAPM 018 IOP Pubishing IOP Conf. Series: Journa of Physics: Conf. Series ( doi : / /1039/1/01030 Tabe 3: Summary of the association between variabes in persona data and cinica data which produced maximum Cramer s V vaue Variabe Chi-square d.f. p-vaue Cramer s V Mae Pneumonia type and ward 14.90** ^ Ward and status of ast contact 14.50** 4 < ^ Length of stay and status of ast contact ** ^ Age and ward ** 4 < ^ Region and ward ** 8 < ^ Femae 0.080^ Ward and status of ast contact ** 4 < ^ Length of stay and status of ast contact 34.66** 4 < ^ Age and ward 79.64** 4 < ^ Region and ward ** 8 < ^ Note: ** significant at p-vaue <0.01, ^maximum Cramer s V vaue for each variabe. Two-dimensiona og-inear modes From Tabe 3, we choose the two variabes which had an association and gave the maximum Cramer s V- vaue to formuate the two-dimensiona og-inear modes, and acquired 9 modes: 5 for mae and 4 for femae, in the form Log[ E( Y ] (. We present ony one mode corresponding to that of age and ward for mae patients in Tabe 4. Tabe 4: The frequencies (percent of age and ward for mae patients Ward Age >0 Tota Pediatric 1161( ( ( (77.31 Medica 0(0.00 9( ( (8.05 Others* 113( ( ( (14.64 Tota 174( ( ( ( Note: * such as neonata, eye, etc. In addition, we have aso fitted the mode under H 0 and the maxima mode under H 1 and obtained χ = , the og-ieihood ratio statistic (D = and degrees of freedom (d.f. = 4, hence at a significance eve 0.05 we reect H 0 and seect the maxima or saturated mode. The estimates of the main effects of interaction terms of the saturated mode are given in Tabe 5. Tabe 5: Estimates of parameters of saturated mode for age and ward for mae patients Parameter Mode under Saturated Parameter Mode under Saturated H mode 0 H mode

7 ICAPM 018 IOP Pubishing IOP Conf. Series: Journa of Physics: Conf. Series ( doi : / /1039/1/01030 The other modes were obtained in the same way. The og-ieihood ratio statistic, chi-square vaue and degrees of freedom for the associated variabes for individua gender are represented in Tabe 6. Tabe 6: The og-ieihood ratio statistic, chi-square vaue and degrees of freedom for associated variabes on mae and femae patients Associated variabes D χ d.f. p-vaue Mae Ward and pneumonia type Ward and status of ast contact <0.001 Ward and age <0.001 Region and ward <0.001 Femae Ward and status of ast contact <0.001 Length of stay and status of ast contact <0.001 Ward and age <0.001 Region and ward <0.001 Three-dimensiona og-inear modes In this section, we determine whether or not any association is the same for both the gender for a patients and age for individua gender. Farr et a. [4], found that crude death rates from pneumonia for mae is more than for femae, that is why gender has been seected as one in each set of three variabes for a patients. We seected age as one in each set of three variabes for individua gender because pneumonia is the infectious cause of death in chidren under the age of 5 [5]. The other two variabes for each set are age and region, pneumonia type and ward, ward and status of ast contact, ength of stay and status of ast contact, age and ward, and region and ward for a patients and pneumonia type and ward, ward and status of ast contact, ength of stay and status of ast contact, age and ward, region and ward for mae patients, and ward and status of ast contact, ength of stay and status of ast contact, age and ward, and region and ward for femae patients. From these, three-dimensiona og-inear modes were formuated using the vaues of deviance difference and deviance difference degrees of freedom to obtain the best modes. The resuts are shown in Tabe 7, however we present ony one mode in detai that is for the ward, status of ast contact and age for femae patients but other modes are aso obtained in the same manner. Tabe 7: Anaysis of deviance for the ward, status of ast contact and age for femae patients Mode Parameter Deviance d.f. Deviance difference d.f. difference (1 Fu mode:,,,, (,(,(,( ( Deete ( from ( * (3 Deete ( from ( * 1 (4 Deete ( from ( * 3 (5 Deete ( from ( * 5 Note: * significant at p-vaue < 0.01 According to the chi-square, the best mode is (, that is Log[ E( Y ] ( ( (, 1, ; 1, ; 1,, which shows that, for femae patients, age is reated with ward and 6

8 ICAPM 018 IOP Pubishing IOP Conf. Series: Journa of Physics: Conf. Series ( doi : / /1039/1/01030 status of ast contact, whie ward is reated to status of ast contact. The observed frequency, expected frequency and standardized residua of ward, status of ast contact and age are shown in Tabe 8. Tabe 8: Observed, expected frequency and standardized residua of ward, status of ast contact and age for femae patients Ce Observed (Expected under H 1 Expected under H 0 Standardized Residua The best mode of three-dimensiona og-inear modes for each set of three variabes is summarized in Tabe 9. According to the three-dimensiona og-inear modes, the best modes for each set of three variabes are not the same. The reationship among variabes in each set contributed for choosing the best mode. From Tabe 8, there is an interaction of three effects in modes (1, (6, (7, (8, (10, (11, (13. Mode (1 shows that the association between age and region is not the same for both the gender. Mode ( iustrates that the distribution of gender is same for the ward and pneumonia type. According to the best mode, mode (3, the association between ward and status of ast contact is the same for both genders. As per mode (4, the association between ength of stay and status of ast contact is the same for both genders. Liewise, mode (5 depicts association of gender being depended on ward and age. Mode (6 shows that the association between ward and region is not the same for both genders. As per mode (7, the dispersa of age is not the same for pneumonia type and ward. Mode (8 and mode (11 demonstrates that the association of ward and status of ast contact is not equivaent for a ages. According to the best mode, mode (9 and mode (1, ength of stay and status of ast contact depended on age. Simiary, modes (10 and (13, the association between age and ward is not the same for region. 4. Concusion In our study, we have shown ony the reative variabes which give the maximum Cramer s V vaue in each tabe of association. There are numerous studies in the word that have investigated on pneumonia. A specia feature of this study is being the first research to be carried out in studying pneumonia patients using og-inear mode in Bhutan and this approach ed to a vauabe resut which can be used by experts in Bhutan to batte against pneumonia. This study showed that most paired variabes were significanty reated at p-vaue ess than For a patients and individua gender, ward has a strong association with pneumonia types, age, status of ast contact and region. In addition, ength of stay has association with status of ast contact. From the numerica resuts, we can see that most of the pneumonia patients are residing in southern region of Bhutan whie there were ess patients from other countries ie Austraia, Bangadesh, India and China receiving treatment in Bhutan. 7

9 ICAPM 018 IOP Pubishing IOP Conf. Series: Journa of Physics: Conf. Series ( doi : / /1039/1/01030 Tabe 9: Summary of the best mode of three-dimensiona og-inear modes Variabes The best mode (1 Age (, region (, and gender ( ( Ward (, pneumonia type (, and gender ( (3 Ward (, status of ast contact (, and gender ( (4 Length of stay (, status of ast contact ( and gender ( (5 Ward (, age (, and gender ( (6 Ward (, region (, and gender ( (7 Pneumonia type (, ward (, and age ( (8 Ward (, status of ast contact (, and age ( (9 Length of stay (, status of ast contact ( and age ( (10 Ward (, region ( age ( (11 Ward (,and, status of ast contact (, and age ( (1 Length of stay (, status of ast contact ( and age ( (13 Ward (, region (, and age ( 1,,3; 1,,3, 4,5; 1, Log[ E( Y ] ( ( (, 1,,3; 1, ; 1, Log[ E( Y ] ( ( ( 1,,3; 1,,3; 1, Log[ E( Y ] ( ( ( 1,,3; 1,,3; 1, Log[ E( Y ] ( ( ( 1,,3; 1,,3; 1, 1,,3; 1,,3, 4,5; 1, 1, ; 1, ; 1,, 3 1, ; 1, ; 1,, 3 Log[ E( Y ] ( ( ( 1, ; 1, ; 1,, 3 1, ; 1,, 3, 4; 13,, 1, ; 1, ; 1,, 3 Log[ E( Y ] ( ( ( 1, ; 1, ; 1,, 3 1, ; 1,, 3, 4; 13,, The prevaence of pneumonia was found to be highest among chidren and mae patients. Since pneumonia is the number one infectious diseases ier of chidren, pediatric ward had the highest number of patients being admitted with more being mae. About 98.7 percent of the patients visited hospita ess than or equas to two days with maority of the patients being admitted in the hospita for ess than or equa to 15 days. Status of ast contact tes us that with ess number of deaths, around 96.1 percent of the patients recovered from pneumonia. Bhutan Mutipe Indicator Survey (010 [6], reveas that about 7% of the chidren are reported to have had the symptoms of Pneumonia and 74% of chidren are said to have received treatment at the heath care unit. Rest 6% have not received any treatment, though 6% seems sma, the batte with pneumonia has 8

10 ICAPM 018 IOP Pubishing IOP Conf. Series: Journa of Physics: Conf. Series ( doi : / /1039/1/01030 not ended. Nevertheess, with awareness campaign on importance of breast feeding, iving in cean surroundings, using antibiotics and vaccines, there are reduction in pneumonia patients with each year. Though the frequency of hospita visits infuences the severity of pneumonia, it coud not find an association with any of the persona and cinica variabes using og-inear modes. The og-inear mode ony determines the association between the variabes [7]. Therefore, another interesting study woud be on pneumonia variabes using ogistic regression modes. References [1] Definition of pneumonia. Avaiabe from [Assessed 1 st June, 017]. [] Causes of pneumonia. Avaiabe from [Assessed 1 st June, 017]. [3] Causes of pneumonia. Avaiabe from [Assessed 1 st June, 017]. [4] Farr MB, Bartett RLC, Wadsworth J, Mier LD. Ris factors for community acquired pneumonia diagnosed upon hospita admission. Respiratory medicine (000 94, [5] Pneumonia, the cause of death in chidren [ Assessed 4 th June, 017] [6] Bhutan mutipe indicator survey. Avaiabe from [Assessed 8 th June, 017]. [7] Tiensuwan M, Yimprayoon P, Lenbury Y. Appication of og-inear modes to cancer patients: A case study of data from the nationa cancer institute, Thaiand. Mahido University. 005: Acnowedgements The authors woud ie to than Thaiand Internationa Cooperation Agency (TICA for the schoarship and record section of Jigme Dori Wangchuc Nationa Referra Hospita (JDWNRH, Ministry of Heath in Bhutan for supporting us with the pneumonia data. 9