A Case-Control Study for Investigating the Effect of Over-The-Counter (OTC) Medications on Renal Function
Date Issued
2006
Date
2006
Author(s)
Chen, Chien-wen
DOI
zh-TW
Abstract
Background
The use of energizing drinks is an unique cultural and health consumption phenomenon in Taiwan. The traditional energizing drinks mostly contain alcohol, which according to the law, are to be sold in the pharmacies only. But the new emerging non-alcoholic energizing drinks are increasingly acquiring market shares and hence promoting the use of energizing drinks outside the traditional target market, the labor class. Also in the non-prescription medication categories the analgesics is the most popular one. Many common cold remedies or cough syrups also contain analgesics, and some even contain caffeine. Alcohol, caffeine, chronic pain, etc are the possible cause of addiction and might lead to the long term use of such remedies or energizing drinks. After long term use of such substances, is it possible that such over-the-counter (OTC) medications might have an influence on the renal function and cause renal function impairment? There is still no consensus on the topic nor related studies on this field.
Purpose of the study
In our daily life, some people regularly use OTC analgesics and energizing drinks for a long time, and there are not only analgesics but also alcohol and caffeine which might lead to addictive use of such substances, and combination use of such analgesics might be possible. It is our main purpose to investigate that the long term use of these kinds of substances might cause renal insufficiency or not. If so, the current regulations of the OTC medications and energizing drinks might need to be changed.
Designs and methods
We conducted a case-control study in the Municipal Gandau Hospital during Mar 20 to Apr 10, 2006. The end-stage-renal-disease (ESRD) patients in the hemodialysis unit, out-patient-department (OPD) clinic patients in the family medicine department (FM), and the ones from the health checkup center for health chekup were enrolled. Questionnaires were issued to acquire the exposure history of the related substances and other related confounding covariates. Laboratory data were linked from the computer database in the hospital by personal ID number. Cases were defined as following: 1.serum creatinine (Cr) >1.5mg/dl, 2.urine protein >3+, 3.ESRD patients. The rest who didn’t fulfill the above criteria were taken as controls. The t test, Chi-square test were performed to analyze the difference between the two groups and logistic regression analyses were performed for the odds ratio (OR) of the related covariates.
Results
We collected totally validated 343 questionnaires, and 201 ones were processed into a computer database since the efficient ratio for the case/control was 1/4 for the statistics. There were 39 cases from the dialysis unit and one from the FM OPD clinic whose Cr was 1.7mg/dl and urine protein was negative. There were totally 161 controls, 126 from the FM OPD, 19 from the health checkup center and 16 hospital employees. 103 were male and 98 were female. After analyzing the demographic covariates, the case group was older than the control group, had lower education level and income. The average body weight of the case group was also lighter than that of the control group. Using 24 for the cut-off point of body mass index (BMI) as suggested by the Department of Health, the control group had more people who were overweighted.
The average smoking (or ever smoked) rate was 35.5%, and alcoholics drinking rate was 75.3%, 15 people (or totally 7.54%) had the habit of betal nuts chewing. 144 people (74.2%) had eaten instant noodles, 69 people (35.6%) had taken Chinese medicine. There were no statistically significant differences in the smoking, alcoholics drinking, betal nuts chewing and instant noodles consumption covariates between the case and control groups.
There were totally 20 people (10.2%) who had used the traditional alcohol-containing energizing drinks. 33 people(16.9%) had used the new emerging non-alcohol-containing energizing drinks. Accounting for both the traditional and new emerging energizing drinks there were 43 people (22.05%) who used the energizing drinks, 20% in the case group and 22.58% in the control group. Statistically there was no significant difference between the two groups (p=0.73).
Totally 100 people (51.3%) had used medications for headache/migraine, toothache, lower back pain/sciatica, and menorralgia. 99 people (50.3%) had specifically confirmed that they had purchased analgesics from the pharmacies. To sum up there were 123 people (63.1%) who had used medications for pain symptoms or were known had purchased analgesics from pharmacies. There were 103 people (52.3%) who had purchased common cold drugs or syrups from the pharmacies. To add up all the above criterias, there were 155 people (78.7%) who had used medications for pain symptoms or had purchased common cold drugs or syrup from the pharmacies or had known purchased analgesics from the pharmacies. The prevalence of the use of OTC drugs was high due to the convenience.
After analyzing the demographic data with single variate logistic regression analysis, there were significant differences in the covariates of age, education level, and body weight between the case and control groups. The risk for renal insufficiency was lower when the education level was higher, or when the income was higher, or when the body weight was heavier. And there was also significant difference both in the education level and income with trend test (p<0.05). The renal impaired cases seemed to have lower BMI, and there seemed to be a linear trend effect when BMI was divided into 4 groups when using 18, 25, 28 as cut-off values. And there was also statistically significant difference with trend test. In the lifestyle covariates, only the covariate of consumption of Chinese medicine was statistically significant related. The odds ratio (OR) was 2.43 for the Chinese medicine users when comparing with the non-users.
In the energizing drinks covariates, there was no significant difference when using any single energizing drinks, or traditional alcohol-containing ones, or new emerging non-alcoholic ones, or any energizing drinks as covariate due to the large p values. Only the OR for a single energizing drinks (Love Liver oral liquid) was 1.99(0.351-11.255), but the p vale was 0.44 and exceeded 0.05 so there was no significant difference. It might be due to the small number of samples and the low consumption rate of energizing drinks so that there was sparse information in the dataset which lead to insignificance.
After controlling the age, gender, education level, income, and body weight covariates which were differently distributed between the case and control groups, the ones with the personal history of hypertension, cardiovascular diseases, diabetes mellitus, nephritis, gout, and proteinuria tended to have higher risk of renal impairment. However, the disease of osteoarthritis which might cause higher use of non-steroidal anti-inflammation drugs (NSAIDs) was not significant related to the renal impairment. Auto-immune dieases, cancers, hepatitis were not related to renal impairment.(but the case numbers of auto-immune diseases or cancers were both very small)
In the life style covariates, though the OR all exceeded 1 in the smoking, alcoholic drinking, betal nuts chewing covariates but there was no statistical significance. But there were significant relationships for both the Chinese medicine consumption and instant noodles consumption covariates with renal impairment. The OR for the use of instant noodles was 3.36 (1.191-9.467) and the OR for the use of Chinese medicine was 3.25 (1.394-7.576). Further analysis revealed the OR elevated to 6.30 (1.551-25.59) when one had used either instant noodles or Chinese medicine, and the risk was even higher for those who used both the instant noodles and Chinese medicine with the OR up to 27.65(4.001-191.118). There was interaction between the instant noodles consumption and the diabetes mellitus so stratification analysis were made for the diabetes mellitus. For those who had diabetes mellitus, the instant noodles consumption caused an elevated OR up to 12.75 (2.123-76.566) when using single variate analysis and the OR was even higher after controlling age, gender, education level, income and body weight in the multivariate logistic regression analysis. But the interpretation of such results should be careful due to the small case number in the DM group (N=35 only after stratification). In the non-DM group, the consumption of instant noodles showed no significant effect on the renal impairment.
In the OTC analgesics covariates, there was no significant risk for renal impairment after controlling the age, gender, education level, income and body weight when using multivariate logistic regression analysis, no matter using the covariates of using the medication for pain symptoms, or purchasing common cold drugs or syrups in the pharmacies, or using either one of the above.
And there were also no significant risk for renal impairment on the use of energizing drinks after controlling age, gender, education level, income and body weight.
If we treated the tradition alcohol-containing energizing drinks as OTC medication and pooled with the other analgesics, common cold medications, and syrups all together as a new covariate as using all possible OTC medications, there was still no significant risk for renal impairment after controlling age, gender, education level, income and body weight.
The reason why this study cannot show the influence of the analgesics or energizing drinks on renal impairment could be due to the recall bias and selection bias which resulting the under estimate of the exposure of the OTC medications and energizing drinks, lacking the cases of early renal impairment, the under estimate of the exposure of the case group due to the influence of the doctor and mass media, and the cohort effect might also be the reason of the low exposure of the case group. Though the instant noodles and Chinese medicine consumption showed increased odds of being renal impaired, they might be proxies for other unknown factors which related to renal impairment and needed to be further investigated.
Conclusion
The study investigated the influence of the OTC (including the energizing drinks and analgesics) medications on the renal function, and revealed no significant relationship before or after controlling the demographic covariates. But there was significant relationship between renal impairment and Chinese medicine consumption, and there was also significant relationship between renal impairment and instant noodles consumption for those with DM. After controlling the basic demographic covariates, the OR for the instant noodles users was 3.36 (1.191-9.467) and the OR for the Chinese medicine users was 3.25 (1.394-7.576). The OR for those using either one of the above was 6.30 (1.551-25.59) and the OR was even higher when using both of the above up to 27.65 (4.001-191.118). The OR before controlling the basic demographic covariates for instant noodles users in the DM group was 12.75 (2.123-76.566) and the risk was higher after controlling the basic demographic covariates as mentioned above with the OR up to 21.16 (1.518-294.919). But due to the small number of the cases of DM group(N=35), the interpretation of such result should be taken with caution. The OTC analgesics and energizing drinks in the case group might be under estimated due to some study methods limitation. The instant noodles and Chinese medicine consumption was related to renal impairment but they might be proxies for other unknown factors or covariates and needed to be further investigated.
Subjects
成藥
指示藥品
止痛藥
提神飲料
止痛糖漿
感冒糖漿
腎功能不良
生活習慣
中藥
泡麵
Over-the-counter
OTC
analgesics
energizing drinks
analgesic syrup
cough syrup
renal insufficiency
renal impairment
renal failure
ESRD
life style
Chinese medicine
instant noodles
SDGs
Type
thesis
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