38
agreement between classification of tubal blockage using chlamydia index and tubal blockage using hysterosalpingogram. Kappa values can be interpreted thus; ≤ 0 indicates no agreement, 0.01-0.20 shows none to slight agreement, 0.21- 0.40 shows fair agreement, 0.41-0.60 shows moderate agreement while 0.61 – 0.80 shows substantial agreement and 0.81 – 1.0 shows an almost perfect agreement.75 All (independent) variables that were significant (p < .05) on bivariate analysis were entered at once at the beginning to assess their predictive ability. The quality of the model was adjudged good when the Omnibus tests of model coefficients were significant (i.e., p < .05) and the Hosmer–Lemeshow goodness-of-fit test value was >0.05. Confidence interval was set at 95% for all statistical tests. P value of < 0.05 was considered statistically significant.
5.12 Ethical Consideration
Approval for the study was obtained from the Health Research and Ethics Committee of the Lagos State University Teaching Hospital, Ikeja, Lagos State. The research participants for the study were assured of confidentiality and data collected were deidentified so that the identity of the subjects was not revealed. This can be seen as appendices I and ii, found on pages 62 and 64 respectively.
39 STRENGTHS OF THE STUDY
1. The use of a relatively larger sample size 147 from each group in the present study.
2. The use of an ELISA test kit that was both qualitative and quantitative. This test has been shown to have a very high specificity of 98.5%. It is readily available, less invasive and easier to perform.
3. It offers an option for patients who are afraid of performing HSG as a first line of tubal patency assessment.
4. The test is of relatively low cost compared to HSG with no complications.
LIMITATIONS
1. Hysterosalpingography cannot conclusively show that non demonstrable tubal blockage may be due to tubal spasm, the use of laparoscopy and chromotubation would have assisted in diagnosing tubal block as it is the gold standard in diagnosing tubal factor infertility.
2. The non-use of the micro-immunoflourescence (MIF) assay which is the gold standard in detecting serum Chlamydia antibodies, however, it is laborious, time consuming and not commercially available.
3. The possible cross reactivity of other species of Chlamydia with Chlamydia trachomatis antibodies.
4. In the diagnosis of tubal blockage on hysterosalpingography, bilateral tubal blockage could have been caused by other factors like endometriosis and previous pelvic surgery or organisms such as nieserria gonorrhea, mycoplasma hominis, mycoplasma genitalium and mycobacterium tuberculosis.
40 CHAPTER SIX
RESULTS
This study was conducted between 27th June 2016 and 28th October 2016. Of the desired sample size of 155 for each group calculated earlier, only 147 subjects completed the study.
The socio-demographic characteristics of the cases and controls are presented in Table 1.There was no significant difference in the mean age of cases (36.5±5.6) and controls (35.4±5.7) (p = 0.694). All study participants were married. There was no statistically significant difference in the educational status of cases and controls (p = 0.677) and majority of the study participants had tertiary education 92 (62.6%) cases and 88 (59.9%) controls There was no significant difference in the socioeconomic status, tribe and BMI of cases and controls (p > 0.05), however majority of cases and controls were middle class (75.5% vs.
66.6%), Christians (70.7% vs. 79.6%), Yorubas (66.7% vs. 66.7%) and overweight (39.5% vs.
44.2%).
41 Table 1: Socio demographic characteristics of subjects
_____________________________________________________________________________
Variable Case Control x2 p
n = 147 (%) n = 147 (%)
______________________________________________________________________________
Age group (years)
< 30 12 (8.2) 15 (10.2) 1.45 0.694 30 – 34 42 (28.6) 49 (33.3)
35- 30 52 (35.4) 47 (32.0)
≥ 40 41 (27.9) 36 (24.5)
Mean±SD 36.5±5.6 35.4±5.7
Educational level
None 1 (0.7) 0 (0.0) 1.525 0.677
Primary 10 (6.8) 13 (8.8) Secondary 44 (29.9) 46 (31.3) Tertiary 92 (62.6) 88 (59.9) Socio economic status
Low 36 (24.5) 50 (34.0) 3.221 0.073
Middle 111 (75.5) 97 (66.0)
Religion
Christianity 104 (70.7) 117 (79.6) 3.080 0.079
Islam 43 (29.3) 30 (20.4)
Tribe
Yoruba 98 (66.70 98 (66.7) 0.415 0.937
Hausa 3 (2.0) 3 (2.0)
Igbo 19 (12.9) 16 (10.9) Others 27 (18.4) 30 (20.4) BMI
Underweight 2 (1.4) 1 (0.7) 2.11 0.549
Normal 40 (27.2) 44 (29.9)
Overweight 58 (39.5) 65 (44.2)
Obese 47 (32.0) 37 (25.2)
______________________________________________________________________________
42 NB: Age range = 22 – 49 years
Socioeconomic class was defined by the husband’s occupation
The clinical characteristics of cases and controls are presented in Table 2a and 2b. There was no significant difference in parity, number lifetime sexual partners, age at first sexual intercourse, history suggestive of PID, abnormal vaginal discharge, lower abdominal pains, fever and chronic pelvic pains between cases and controls (p>0.05). A significantly higher proportion of cases compared to controls had history of induced abortion (53.1% vs. 38.1%), post abortal/ puerperal sepsis (12.9% vs. 2.0%), secondary infertility (91.7% vs. 76%), used condoms (25.9% vs. 16.3%) and oral contraceptive (21.1% vs.8.2%) (p <0.05).
43 Table 2a: Clinical characteristics of case and controls
______________________________________________________________________________
Variable Case Control x2 p
n = 147 (%) n = 147 (%)
______________________________________________________________________________
Parity
Nulliparous 103 (70.1) 106 (72.1) 0.149 0.700
Multiparous 44 (29.9) 41 (27.9)
Type of infertility
Primary 12 (8.3) 35 (24.0) 13.236 <0.001*
Secondary 133 (91.7) 111 (76.0)
Duration of infertility (years)
1 – 5 70 (47.6) 96 (65.3) 9.368 0.009*
6 – 10 49 (33.3) 22 (22.4)
>10 28 (19.0) 18 (12.2)
History of induced abortion
Yes 78 (53.1) 56 (38.1) 6.637 0.010*
No 69 (46.9) 91 (61.9)
Number of induced abortion
None 69 (46.9) 91 (61.9) 7.86 0.049*
1 30 (20.4) 24 (16.3)
2 27 (18.4) 17 (11.6)
≥ 3 21 (14.3) 15 (10.2)
Coitarche (years)
< 18 23 (15.6) 15 (10.2) 1.934 0.164
≥18 124 (84.4) 132 (89.8)
Lifetime sexual partner(s)
1 10 (6.8) 16 (10.9) 8.451 0.076
2 41 (27.9) 49 (33.3)
3 29 (19.7) 34 (23.1)
4 34 (23.1) 32 (21.80
≥5 33 (22.4) 16 (10.9)
Mean±SD 2.69±2.4 1.94±1.3
______________________________________________________________________________
NB: * = Significant
44 Table 2b: Clinical characteristics of case and control
__________________________________________________________________________________
___
Variable Case Control x2 p
n = 147 (%) n = 147 (%)
__________________________________________________________________________________
___
Abnormal vaginal discharge
Yes 99 (67.3) 94 (63.9) 0.377
0.539
No 48 (32.7) 53 (36.1)
Lower abdominal pains
Yes 53 (36.1) 47 (32.0) 0.546
0.460
No 94 (63.9) 100 (68.0)
Fever
Yes 25 (17.0) 21 (14.3) 0.412
0.521
No 122 (83.0) 126 (85.7)
History suggestive of PID
Yes 58 (39.5) 65 (44.2) 0.685
0.408
No 89 (60.5) 82 (55.8)
Chronic pelvic pains
Yes 12 (8.2) 17 (11.6) 0.956
0.328
No 135 (91.8) 130 (88.4)
History of post abortal / puerperal sepsis
Yes 19 (12.9) 3 (2.0) 12.578
<0.001*
No 128 (87.1) 144 (98.0)
Condom use
Yes 38 (25.9) 24 (16.3) 4.006
0.045*
No 109 (74.1) 123 (83.7)
Use of OCP
Yes 31 (21.1) 12 (8.2) 9.834
0.002*
No 116 (78.9) 135 (91.8)
Use of IUCD
45
Yes 3 (2.0) 0 (0.0) 3.031
0.247
No 144 (98.0) 147 (100.0)
Table 3: Sensitivity and specificity of Chlamydia antibodies
__________________________________________________________________________________
_
Chlamydia antibodies HSG REPORT
Non-Patent tubes Patent tubes Total
n = 147 (%) n = 147 (%) n= 294 (%)
__________________________________________________________________________________
__
Positive 103 (70.1) 38 (25.9) 141 (48.0)
Negative 44 (29.9) 109 (74.1) 153 (52.0)
__________________________________________________________________________________
___
Total 147 (100.0) 147 (100.0) 294 (100.0)
a = 103, b = 38, c = 44, d = 109 x2 = 57.579 p < 0.001*
Sensitivity – 𝑎+𝑐𝑎 = 103/147 = 70.1%
Specificity = 𝑏+𝑑𝑑 = 109/147 = 74.1%
Positive predictive value = 𝑎+𝑏𝑎 = 103/141 = 73.0%
Negative predictive value = 𝑐+𝑑𝑑 = 109/153 = 71.2%
46 Accuracy = 𝑎+𝑏+𝑐+𝑑𝑎+𝑑 = 103 + 109 / 294 = 72.1%
Kappa = 0.442*
The prevalence of Chlamydia trachomatis antibodies amongst the study participants was 48% i.e. 141 out of 294 participants were positive to the test. The validity of the Chlamydia serology tests using HSG results as standard revealed a sensitivity of 70.1% and a specificity of 74.1%. The accuracy of chlamydia serology test to distinguish subjects with bilateral tubal blockage diagnosed with HSG was 72.1% as shown in Table 3. Non patent fallopian tubes was significantly associated with positive Chlamydia Ig G index (p <0.001). Kappa (inter rater reliability coefficient) which examines the agreement between two categorical variable was 0.442, thus making the agreement between HSG and CAT in assessing tubal blockage, a moderate one.
47
Figure 1: showing the seropositivity and seronegativity amongst the cases and controls.
Amongst cases 103 (70.1%) had seropositivity to the Chlamydia antibody test while 38 (25.9%) of the controls had seropositivity to the test. This was statistically significant with p of <0.001 as shown in table 3.
70.10%
29.90%
25.90%
74.10%
Positive Negative
Case (n = 147) Control (n = 147)
48
Figure 2: Histogram plot showing the distribution of Chlamydia antibody index
Histogram plot showing the distribution of Chlamydia Ig G antibody index. The chlamydia antibody index was not normally distributed among the study participants necessitating the use of median instead of mean.
The factors associated with chlamydia antibody index are shown in Table 4a and 4b. History of induced abortion and type of infertility were significantly associated with positive chlamydia index in this study. A significantly higher proportion of subjects with induced abortion (54.7%) compared with 42.8% without induced abortion had positive chlamydia antibody index (p = 0.043) while 51.2% of subjects with secondary infertility compared with 29.8% subjects with primary infertility had positive chlamydia index (p = 0.007). Parity, number of lifetime sexual partners, age at first sexual intercourse, number of induced
49
abortion, history of suggestive of PID, post abortal/puerperal sepsis, abnormal vaginal discharge, lower abdominal pains, fever, chronic pelvic pains, use of condoms, OCPs and IUCD as well as duration of infertility were not significantly associated with positive chlamydia index (p >0.05).
Table 4a: Factors associated with Chlamydia Ig G antibody index
__________________________________________________________________________________
___Variable Chlamydia index
Positive Negative x2 p
n = 141 (%) n = 153(%)
__________________________________________________________________________________
Parity
Nulliparous 95 (45.5) 114 (54.5) 1.817
0.178
Multiparous 46 (54.1) 39 (45.9)
Type of infertility
Primary 14 (29.8) 33 (70.2) 7.262
0.007*
Secondary 125 (51.2) 119 (48.8)
History of induced abortion
Yes 70 (54.7) 58 (45.3) 4.112
0.043*
No 71 (42.8) 95 (57.2)
Number of induced abortion
None 70 (49.6) 90 (58.8) 4.887
0.180
1 27 (19.1) 27 (17.6)
2 21 (14.9) 23 (15.0)
≥3 23 (16.4) 13 (8.6)
Coitarche (years)
< 18 20 (52.6) 18 (47.4) 0.382
0.537
≥18 121 (47.3) 135 (52.7)
Multiple sexual partners
Yes 129 (48.10 139 (51.9) 0.037
0.847
No 12 (46.2) 14 (53.8)
Duration of infertility (years)
50
1 -0 5 76 (45.8) 90 (54.2) 0.779
0.677
6 – 10 41 (50.0) 41 (50.0)
>10 24 (52.2) 22 (47.8)
Table 4b: Factors associated with Chlamydia Ig G antibody index
__________________________________________________________________________________
___Variable Chlamydia index
Positive Negative x2 p
__________________________________________________________________________________
___Abnormal vaginal discharge
Yes 93 (48.2) 100 (51.8) 0.012 0.914
No 48 (47.5) 53 (52.5)
Lower abdominal pains
Yes 50 (50.0) 50 (50.0) 0.253 0.615
No 91 (46.9) 103 (53.1)
Fever
Yes 22 (47.8) 24 (52.2) 0.000 0.984
No 119 (48.0) 129 (52.0)
Chronic pelvic pains
Yes 12 (41.4) 17 (58.6) 0.558 0.455
No 129 (48.7) 136 (51.3)
History of suggestive of PID
Yes 61 (49.6) 62 (50.4) 0.226 0.234
No 80 (46.8) 91 (53.2)
History of post abortal/puerperal sepsis
Yes 13 (59.1) 9 (40.9) 1.181 0.277
No 128 (47.1) 144 (52.9)
Use of condoms
Yes 33 (53.2) 29 (46.8) 0.873 0.350
No 108 (46.6) 124 (53.4)
Use of OCPs
Yes 23 (53.5) 20 (46.5) 0.617 0.432
No 118 (47.0) 133 (53.0)
Use of IUCD
Yes 3 (100.0) 0 (0.0) 3.289 0.109
No 138 (47.4) 153 (52.6)
__________________________________________________________________________________
__
51
Table 5: Factors associated with positive Chlamydia Ig G index
__________________________________________________________________________________
___Variable Chlamydia Ig Index U p
Median (IQR)
__________________________________________________________________________________
___Tubal blockage
Yes 1.06, (IQR 0.59, 1.65) 4066. <0.001*
No 0.47, (IQR 0.29, 0.82)
Parity
Nulliparous 0.64, (IQR 0.36, 1.34) 5820.5 0.741
Multiparous 0.73 (IQR 0.37, 1.32)
Multiple sexual partners
Yes 0.67 (IQR 0.37, 1.34) 2310.5 0.677
No 0.25 (IQR 0.25, 1.41)
Coitarche
<18 0.76 (IQR 0.41, 1.17) 2998.5 0.559
≥ 18 0.65 (IQR 0.35, 1.34)
History of PID
Yes 0.72 (IQR 0.36, 1.46) 6957.0 0.514
No 0.62 (IQR 0.37, 1.31)
History of induced abortion
Yes 0.74 (IQR 0.40, 1.47) 6202.0 0.045*
No 0.64 (IQR 0.33, 1.22)
History of postabortal/ puerperal sepsis
Yes 0.85 (IQR 0.40, 1.31) 1543.5 0.511
No 0.66 (IQR 0.35, 1.34)
Type of infertility
Primary 0.47 (IQR 0.28, 0.85) 3112.0 0.009*
Secondary 0.72 (IQR 0.39, 1.38)
__________________________________________________________________________________
___
NB = * Significant U = Mann Whitney U test
Chlamydia Ig G index range = 0.02 – 7.0
52
Table 5 shows that the median Chlamydia Ig G index of subjects with tubal blockage was significantly higher (1.06 IQR 0.59, 1.65) than those without tubal blockage (0.47 IQR 0.29, 0.82) p <0.001. Median Chlamydia Ig G index of subjects with history of induced abortion and secondary infertility was significantly higher than subjects with no history of induced abortion and primary infertility respectively (p <0.05). Parity, multiple sexual partners, coitarche, history of suggestive of PID and history of post abortal/puerperal sepsis was not significantly associated with positive chlamydia Ig G index (p > 0.05).
Table 6: Logistic regression of predictors of positive chlamydia Ig G index
Variable p odds ratio* 95%CI
Primary infertility 1
Secondary infertility 0.316 1.474 0.690 – 3.151
No induced abortion 1
Induced abortion 0.914 1.031 0.595 – 1.787
No tubal blockage 1
Tubal blockage <0.001 6.371 3.793 – 10.699
NB = * Adjusted odds ratio
53
Table 6 illustrates multivariate analysis of predictors of positive Chlamydia Ig G index. Tubal blockage made significant contribution to explaining positive Chlamydia Ig G index. Subjects with tubal blockage had over six-fold chance (OR 6.371 95%CI 3.793 – 10.699) of having positive chlamydia Ig G index compared to subjects with no tubal blockage after accounting for type of infertility and induced abortion.
CHAPTER SEVEN
DISCUSSION, CONCLUSION AND RECOMMENDATION
54
The commonest cause of infertility in our environment is tubal disease which is attributed to post abortal sepsis, post partum infection and sexually transmitted infections.13 Chlamydia trachomatis is considered to be a leading cause of sexually transmitted infections and female infertility worldwide 18 The overall prevalence of Chlamydia trachomatis Ig G antibody in this study was 48%. This finding is higher than that reported in earlier studies done in Nigeria from LUTH (35.3%), Ibadan (20.5%) and Benin (20.5%) 76.77,71 Other studies, done outside Nigeria (Egypt, The Netherlands and India) reported lower prevalence rates of 23%, 37.5%, 36.6%, 5%. 64,78,79,80 respectively. The value obtained from this study is however low compared to what was reported in a similar study from Port Harcourt where an overall prevalence of 74% was obtained.72
The lower prevalence rates reported by studies 64,71,76,77,79,80 may be due to the kind of study population and the participants used in these studies; most were cross-sectional studies involving all patients either attending the infertility clinic or those undergoing diagnostic evaluation for infertility, although the study done in Benin was case control, it used antenatal patients who are generally expected to have low prevalence as controls.
Although, Port Harcourt has similar cosmopolitan features like Lagos, the test kit used for the study was qualitative compared to the combined qualitative and quantitative test kits used in this present study which is expected to give more accurate result.
The increase in number of sexually transmitted infections and pelvic inflammatory disease worldwide may not be unconnected to the high prevalence of chlamydial antibodies in this study. The indiscriminate use of information technology especially the social media could contribute to the global rise in sexually transmitted infections as adolescents and youth could have access to unguarded websites hence encouraging risky sexual behaviours. In addition, the infection is largely asymptomatic and the poor diagnostic facilities in our
55
environment could lead to under and mis-diagnosis of most infections which may also account for the finding in this study. Cases of unsafe abortions and puerperal sepsis are still rampant in our environment, leading to late sequelae of the disease.
The sensitivity of Chlamydia antibodies as a diagnostic marker for tubal factor infertility was 70.1% in this study. This is comparable to figures obtained from a cross sectional study from Lagos, where chlamydia antibody was assessed in all patients who underwent hysterosalphingography, revealing a sensitivity of 65.7%. 76 Studies done in Benin (68.4%), Port Harcourt (78.4%) and India (72.7%) 71,72,40 also had comparable figures like the one obtained from this study. Lower seropositivities were obtained from studies from Egypt (30%) 79, the Netherlands (45%) 64 and India (20%). 80 However, another study from Egypt, where 80 women had diagnostic laparoscopy for assessment of tubal infertility showed a sensitivity of 85.7% (23/27).78
Studies 40,71,72,76 with comparable sensitivities as found in this study also employed HSG as a diagnostic method for tubal blockage while the ELISA Ig G test kit was also used in the laboratory detection of serum Chlamydia antibodies. Lower sensitivities reported from other studies could be due to regional differences that could exist, varying laboratory procedures as well as differences in cut off points from 1:16 to 1: 64. The cross sectional nature of the studies could also account for low sensitivities obtained from these studies
64,80 as all the patients undergoing laparoscopy for infertility evaluations were recruited thus giving rise to a group of research participants with various causes of infertility like uterine, ovulatory, unexplained as well as tubal amongst the group of patients that participated. Singh et al 80 reported the area of study as endemic for tuberculosis, hence, this could have been a major cause of tubal blockage in these women.
56
The sensitivity of the test in this study was 70.1%, which was quite high. Factors responsible for this could have been the nature of the test kit used. The ELISA test kit had a sensitivity of 91.1% and a specificity of 98.5%.60 The test was both qualitative and qualitative in interpretation of results. The quantitative nature would have removed the observer error as the patients’ Chlamydia Ig G antibody levels were represented in figures.
Hysterosalphingography employed to diagnose tubal patency in this study has its limitations giving rise to false positives HSG results due to either tubal spasm or other infectious causes of tubal blockage.
The specificity of 74.1% was obtained in this study; this was comparable to specificities of 77.7% in India40 and 76.2% in Ibadan.77 Higher specificities of 83%, 84.6%, 100% respectively
64,78,80 reported from some other studies could have been due to use of laparoscopy and chromotubation to define tubal blockage. This would have eliminated the possibility of tubal spasm on HSG as cases with genuine tubal blockage would have been diagnosed by the laparoscopy and chromotubation, reducing the number of false positives.
In this study, kappa which is the degree of agreement between chlamydia index and HSG in diagnosis tubal blockage beyond chance was moderate. This finding is expected as other infective causes of tubal blockage such as nieserria gonorrhea, mycoplasma hominis, mycobacterium tuberculosis as well as tubal occlusion form tubal spasm may explain the limitation of a positive chlamydia antibody index to serve as a predictor of tubal blockage.
Some workers have suggested its use as a screening test for tubal infertility before more expensive and invasive investigative procedures like HSG, laparoscopy and chromotubation are carried out 29,76,77,78,79 or as a viable option were access to HSG is lacking especially in developing countries. 40,72
57
Tubal blockage was significantly associated with the presence of serum Chlamydia antibodies as was found in other similar studies. 31,32,40,59,71,72,76,77,78,79 This was corroborated in table 5 where tubal blockage was significantly associated with a higher median value of Chlamydia Ig G index; 1.06, (IQR 0.59, 1.65) compared to those without tubal blockage 0.47, (IQR 0.29, 0.82). This was also shown in a similar study by Thomas et al, 32 where significantly higher titres of Chlamydia antibody titres of 1 in 128 or more were found in women with tubal blockage.
From the present study, history of induced abortion was found to be significantly associated with positive chlamydial Ig G index (p = 0.045) as the median Chlamydia Ig G index of subjects with history of induced abortion [0.74 (IQR 0.40, 1.47)] was significantly higher than those without induced abortion [0.64 (IQR 0.33, 1.22)]. This study also showed that secondary infertility was significantly associated with positive Chlamydia Ig G index compared to those with primary infertility (p=0.009). This was also reported by Okunlola et al15 in a study where patients with secondary infertility had significantly higher titres than those with primary infertility (p <0.05). However, tubal blockage made significant contribution to explaining positive chlamydia index. Subjects with tubal blockage had over six-fold chance (OR 6.371 CI 3.793 – 10.699) of having positive chlamydia Ig G index compared to subjects with no tubal blockage after accounting for type of infertility and history of induced abortion.
CONCLUSION
58
The prevalence of serum Chlamydia antibodies in this study was relatively high and the presence of serum Chlamydia antibodies was significantly associated with tubal factor infertility. Positive values of Chlamydia index were found to be associated with tubal blockage, history of induced abortion and secondary infertility. Serum Chlamydia antibody testing moderately predicts tubal blockage and Subjects with tubal blockage had a six fold chance of having positive Chlamydia Ig G index after accounting for history of induced abortion and secondary infertility.
RECOMMENDATIONS
Serum Chlamydia Ig G antibody testing should be adopted as a screening test for tubal infertility before more invasive and expensive diagnostic procedures are carried out.
Prevention, prompt diagnosis and treatment should be adopted at all levels of healthcare in order to reduce the scourge of this infection.
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