Blood samples for Full Blood Count, Serum Electrolytes and Urea, Random Blood Glucose and Lipid profiles were obtained from each patient. Chest radiograph was done for all the patients.
46 Operational definitions
Dysphagia; acute stroke patients that had negative 10ml water swallowing test and peripheral oxygen desaturation ≥2% were considered to have dysphagia.114-116
Computerized tomography (CT) definition of stroke type: presence of hyperdensity on non-contrast CT (NCCT) brain scan in acute stroke patient is hemorrhagic stroke.
Presence of hypodensity or hypo-attenuation on NCCT brain scan in acute stroke patient defines ischemic stroke.
CT definition of ischemic stroke subtype (OCSP):45
Total anterior circulation infarct (TACI): large anterior circulation infarcts with both cortical and subcortical involvement.
Partial anterior circulation infarct (PACI): predominantly cortical infarcts.
Posterior circulation infarct (POCI): infarcts clearly associated with the vertebrobasilar arterial territory.
Lacunar infarct (LACI): infarcts confined to the territory of the deep perforating arteries.
Limitation of the Study
Inability of all patients with stroke to have neuroimaging done due to cost of the imaging excluded many patients from being recruited and prolonged the time required to achieve the required number of subjects.
47
DATA COLLECTION AND ANALYSIS
Information was obtained from the eligible patients using a questionnaire. Data collection was commenced after an informed consent was obtained from the patient or the relatives of the patient and after ethical approval.
All patients’ socio-demographic and clinical characteristics data were presented in tables and charts using summary statistics of proportions for categorical variables and means± standard deviation for normally distributed continuous variables. The non-parametric variables were presented using median. The Chi-square or its equivalent was used to compare proportions while student t-test or its non-parametric equivalent where appropriate, was used to compare continuous variables. The level of statistical significance was set at p- value of <0.05.
Multivariate logistic regression models were constructed to assess for independent predictors of dysphagia in acute stroke patients with variable that showed significant statistical association with dysphagia both in the study and from literature fitted into the model..
Repeated measures ANOVA was carried out to assess the impact of dysphagia and aspiration on clinical outcome as measured by the Modified Rankin Scale and Barthel Index. Also, survival analysis was done to assess the impact of dysphagia and aspiration on mortality, with Kaplan-Meier curves constructed and Log rank test performed to assess for statistically significance difference. Cox proportional hazard model was used to assess possible causes of death in the patients with dysphagia.
.All data was analyzed using Statistical Package for Social Sciences (SPSS) version 16.
48
CHAPTER FOUR
RESULTS
Four hundred stroke patients presented to UCH during the 9-month study period. Out of the 200
patients that fulfilled the inclusion criteria, ninety nine (99) patients had dysphagia and were recruited as cases while one hundred and one (101) patients who did not have dysphagia were recruited as controls. Reasons for exclusion included inability to do neuroimaging (n=111), pre-hospital delay of more than 7 days (n= 16), repeat stroke (n= 15), GCS less than 8 (n= 35), patient on mechanical ventilator (n= 15), and refusal of the relations to give informed consent (n= 8).
Socio-demographic characteristics of the study population
The dysphagic stroke patients comprised 52 (52.5%) male and 47 (47.5%) female while non-dysphagic stroke consisted of 52 (51.5%) male and 49 (48.5%) female (p= 0.88). The mean ages for the non-dysphagic and dysphagic stroke were 59.5±11.5 years and 62.1±12.1 years
respectively (p= 0.11). The parti ci pants were wel l m at ched for age and s ex as there was no st atis ticall y s igni ficant di fference in age and s ex when the values were com pared bet ween t he d ys phagi c and d ysphagi c st roke groups. All non-dysphagic stroke group and 97 (97.98%) of non-dysphagic stroke were right handed. (p= 0.15).
49
Figure 1: Comparison of gender distribution in dysphagic and non-dysphagic stroke patients
52.5%
51.5%
47.5%
48.5%
44.00%
45.00%
46.00%
47.00%
48.00%
49.00%
50.00%
51.00%
52.00%
53.00%
Cases Controls
Male Female
50 Clinical characteristics of the study population
In this study, hypertension was the most common risk factor for stroke identified in both dysphagic 99 (100%) and non-dysphagic stroke 98 (97.07%). However, there was no statistically significant difference between the two groups (p=0.08).
Diabetes mellitus was not as common as hypertension as a risk factor for stroke in both dysphagic and non-dysphagic stroke in this study. More non-dysphagic stroke group 19 (18.81%) had diabetes mellitus than the dysphagic stroke 15 (15.15%). However, it was not statistically significant. (p=0.49)
The observed difference in GCS at presentation between dysphagic and non-dysphagic was statistically significant (p <0.01). The patients with dysphagia had significantly worse GCS at presentation than the non-dysphagic group as shown in Table 1.
NIHSS of dysphagic stroke patients at presentation (22.81±6.23) was significantly higher than the non-dysphagic group (8.92±6.37). The observed difference was statistically significant (p
<0.01). (Table 1)
TABLE 1: Comparison of GCS and NIHSS of study participants.
Variable Dysphagic Non-dysphagic P-value
GCS at presentation 14-15 9-13
16 (16.16%) 83 (83.84%)
83 (82.18%) 18 (17.82%)
<0.01
NIHSS±SD 22.81±6.23 8.92±6.37 <0.01
. GCS- Glasgow Coma Score. NIHSS: National Institute of Health Stroke Scale.
51
.
The mean pulse rate (p<0.00), systolic blood pressure (p=0.01) and diastolic blood pressure (p=0.03) were significantly higher in dysphagic stroke than in non-dysphagic stroke patients as shown in table 2 below.
TABLE 2: Clinical Characteristics of the Study Population
Variables Dysphagic Non-dysphagic P-value Pulse rate ±SD 93.92± 17.39 86.16 ±12.51 <0.00 Systolic Blood Pressure ±SD 189.67 (38.80) 174.18 (36.77) 0.01 Diastolic Blood Pressure ±SD 109.25 (23.16) 102.35 (20.66) 0.03 Mean arterial pressure 136.10 `126.29 0.04
52
Table 3 shows comparison of laboratory parameters between dysphagic and non-dysphagic stroke patients. The mean random blood sugar observed was significantly higher in dysphagic (167.19±92.26) than non-dysphagic (141.17±57.22). p=0.033.
Dyslipidemia with high total Cholesterol and high LDL-C were observed in both dysphagic and non-dysphagic stroke patients. However, there was no significant statistical difference in the levels of lipid profiles between the dysphagic and non-dysphagic groups as shown in Table 3 (p=
values 0.834, 0.065, 0.161, 0.062).
Table 3: Comparison of laboratory parameters between Cases and Controls
Variables Dysphagic (99) Non-dysphagic (101) P-values RBS at admission (Mg/dL)±SD 167.19±92.26 141.17±57.22 0.033 Lipids Value (Mg/dL)
Total Cholesterol ±SD Triglyceride ±SD HDL-C ±SD LDL-C ±SD
211.8±64.45 128.7±48.57 55.6±21.74 121.4±45.2
208.4±50.08 105.4±39.45 51.0±14.37 134.8±40.29
0.834 0.065 0.161 0.062
53
Table 4 below shows frequency of dysphagia among 200 stroke patients that fulfilled all the inclusion criteria. Using gag reflex method only, the frequency was 99 (49.50%). With 3ml WST only, the frequency was 95 (47.48%). With 10mls WST only, it was 97 (48.50%), and Using Peripheral Oxygen desaturation method, the frequency was 93 (46.47%). 95% confidence interval of each method was as stated in table 4.
TABLE 4: Frequency of dysphagia among stroke admissions during study period.
Variables Frequency Percentage 95% CI
Gag Reflex 99 49.50 43.19 – 54.58
3ml WST 95 47.48 42.49 – 53.59
10ml WST 97 48.50 43.49 – 53.59
Peripheral Oxygen desaturation
93 46.47 41.99 – 53.47
WST: Water Swallowing Test. CI: Confidence Interval
54
More non-dysphagic stroke {65 (64.36%)} than dysphagic stroke patients {35 (35.35%)} had ischaemic stroke while more dysphagic {64 (64.65%)} than non-dysphagic {36 (35.64%)} had haemorrhagic stroke. These differences were statistically significant, p<0.001. (Table 5).
TABLE 5: Distribution of stroke types in dysphagic and non-dysphagic stroke patients.
Variables Dysphagic (%) Non-dysphagic (%) P-value Ischaemic
Haemorrhagic
35 (35.35%) 64 (64.65%)
65 (64.36%) 36 (35.64%)
<0.001
Total 99 101
55
Table 6 shows classification of cerebral infarct based on Oxfordshire Community Stroke Project (OCSP) classification. Four of dysphagic (11.4%) and two of non-dysphagic (3.1%) had TACI.
This was not statistically significant (p= 0.393). 55 of non-dysphagic (84.6%) and 26 of dysphagic (74.3%) had PACI and this difference was statistically significant (p= 0.001). Four of dysphagic (11.4%) and two of non-dysphagic (3.1%) had POCI (p=0.092). 2.9% of dysphagic and 9.2% of non-dysphagic had lacunar syndrome (p= 0.620)
Table 6: Distribution of vascular territories involved in dysphagic and non-dysphagic ischaemic strokes.
Variable Cases (%) (35)
Controls (%) (65)