- Email: [email protected]
MONITORING COCAINE EPIDEMICS IN BARCELONA
450
Assuming average courses of chloramphenicol consisted of 250 mg four times daily for five days (about 100 000 g per month = 240 000 courses annually) and between 1 in 50 000 to 1 in 20 000 of those exposed were to acquire aplastic anaemia,1,2 about 5-12 such cases might be expected in Hong Kong every year. Because many of our patients remain unaware of the drugs they take and because
chloramphenicol-induced aplastic anaemia usually presents many months after exposure,1 we assumed that most cases would never be identified as drug associated but that in Hong Kong there might be a high incidence of aplastic anaemia (irrespective of cause) compared with that in countries where little chloramphenicol was sold. However, according to information provided by the Government of Hong Kong Medical and Health Department, death certification for aplastic anaemia averaged 0.4 per 1000 deaths over 1981-85, compared with 1 0 per 1000 deaths in England and Wales.4 Queen Mary Hospital (which deals with over 50 % of the territory’s serious haematological cases) encountered only 6 new cases of aplastic anaemia in 1985, none linked with chloramphenicol. Possible reasons why an excessive incidence of aplastic anaemia has not been recognised in Hong Kong despite the high rate of chloramphenicol sales, include (1) reduced susceptibility to chloramphenicol-induced aplastic anaemia in the local population; (2) missed diagnosis (though it seems unlikely that patients with severe anaemia would not be admitted to hospital and have a bone examination); (3) that contrary to earlier views, irreversible aplastic anaemia is related to dose and duration of therapy so that short courses with low doses (which, presumably, prevail in Hong Kong) are less risky; and (4) hitherto accepted risks of chloramphenicol-induced aplastic anaemia may be exaggerated. Chloramphenicol sales in Hong Kong are unusually high and probably reflect genuine differences in prescribing priorities and consumption. Nevertheless, the incidence of aplastic anaemia in the community does not appear to be unusual. In many developing countries, chloramphenicol is regarded as a cheap and useful drug for the treatment of many infections and in Hong Kong and elsewhere the infecting organism may be resistant to other common
marrow
antimicrobial agents:
Ampuillin Orgamsm Haemophilus influenzae Streptococcus pneumoniae Salmonella typhi
and paratyphz
% zsolates resistant to: Co-trimoxazole Chloramphenicol
Tetracycline
19
1
1
27
0
25
1
70
1
0
0
N/A
N/A not applicable. Source: microbiology department, University Kong, and pharmacy, Queen Mary Hospital.
of
Hong
Prospective investigations are required to re-evaluate the risk of aplastic anaemia -in countries where widespread use of chloramphenicol continues. We thank Prof T. K. Chan for encouragement and useful discussion and helping to trace cases of aplastic anaemia diagnosed in Queen Mary Hospital in 1985; and Mr N. Li (Medical and Health Department) for statistics on certified aplastic anaemia deaths.
C. R. KUMANA
Pharmaceutical Service, Medical and Health Department,
Hong Kong
K. Y. Li
Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Hong Kong
P. Y. CHAN
1. De Gruchy GC. Aplastic anaemia Drug-induced blood disorders. Oxford: Blackwell Scientific Publications, 1975: 39-75. 2. Vincent C. Drug-induced aplastic anaemia and agranulocytosis incidence and mechanisms. Drugs 1986; 31: 52-63. 3. Annual reports of the Hong Kong Medical and Health Department 1981-1985 (table
22). Mortality statistics: Cause 1981-1985, series DH2 (ICD causes) London: HM Stationery Office.
seem to have favourite indoor sports. Cancer and heart disease, obesity and anorexia, and mental illness and drug abuse-we fear them all. But over time we lose interest in one after another and turn our attention to a new peril and a new protection. Now it is AIDS. Everyone is at risk. The disease is so contagious that some medical personnel and undertakers refuse to care for and bury the victims. It is so costly that soon it will bankrupt us. Such are the claims. What is there to do? Spend more on research; test immigrants and even tourists; quarantine homosexuals; give addicts free needles? Such are the proferred solutions. Let us try to look at AIDS through the lens of history instead of hysteria. When the US Surgeon General compares AIDS to the Black Death, he may be on to something neither he nor the American people are prepared to face. For who (except some historians) now realises that the Black Death killed one-third of Europe’s population because, in the absence of cats, rats multiplied and spread the plague? Why were there no cats? Because there was a war on witches, and cats, being the witches’ helpers, were exterminated. The spread of AIDS is now due, at least in part, to addicts’ use of dirty needles. Why are there suddenly so many dirty needles around? Because there is a war on drugs, and needles, being the addicts’ helpers, are outlawed. One-quarter or more of all AIDS victims in the United States are addists. Half of New York City’s 200 000 heroin addicts are said to carry HIV. Their sexual contacts transmit the virus to the heterosexual population. If drugs and needles could be bought like beer and beer glasses addicts would not need to use dirty needles. Suppose that a remedy were at hand that would virtually guarantee to reduce the incidence of AIDS overnight by at least one-third; that the remedy were medically safe (ie, it would produce no biologically deleterious side-effects); and that it would cost us nothing, would save us vast sums expended on law enforcement, and would make our homes and streets safer. Would this remedy be embraced as a godsend--or would it be rejected as the very handiwork of the devil? The facts speak for themselves--and what they tell us is disheartening. Politicians pontificate about the free market to protect American exports, such as cigarettes, but consider it anathema even to contemplate a free market in drugs. Would such a policy increase heroin addiction in exchange for a decreased incidence of AIDS? Perhaps. Perhaps not. In any case, were drugs and needles available like beer and beer glasses, how many Americans would want to inject heroin into their bodies? I doubt that the number is as dangerously great as the threat posed by AIDS.
SIR,-Fearing health hazards and fighting them
become
’
our
University Hospital, Department of Psychiatry, SUNY Health Science Center, Syracuse, NY13210, USA
THOMAS S. SZASZ
MONITORING COCAINE EPIDEMICS IN BARCELONA
SiR,—The monitoring of drug-related problems in emergency is a good indicator for epidemiological surveillance of drug dependence.1,2 This system can detect increases in drug abuse prevalence as well as sudden changes in patterns of abuse. Since 1979, in the Hospital del Mar, Barcelona, we have monitored toxicological emergencies. We detected a sudden rise in heroin-related casualties in December, 1981, preceding a large and steady increase in admissions to opioid-treatment faCilitiM3In October, 1986, a sudden increase of cocaine-admissions was
rooms
Department of Medicine, University of Hong Kong, Queen Mary Hospital, Hong Kong
4.
AIDS AND DRUGS: BALANCING RISK AND BENEFITS
no
284 and deaths from all
detected. The number of casualties has remained increased since (figure). A major proportion of these cocaine-related problems comes from its intranasal use. During the past year, 57% of cocaine-related admissions were because of withdrawal problems, 24% were overdoses, and 19% were because of ’other complications. In contrast, heroin-related emergencies have remained stable at a mean of 225 per month.4 These fmdings indicate that a large increase of cocaine consumption occurs in Barcelona in groups other than intravenous drug abusers. This signal, found in a simple monitoring system,
451 PERCENTAGE
FREQUENCY OF OCCURRENCE OF PSYCHIATRIC
SYMPTOMS AND VIOLENCE IN DIFFERENT GROUPS OF COCAINE USERS
Quarterly
mean
of cocaine-related
emergencies
in
Hospital del
Mar, Barcelona. should allow the municiple authorities to undertake quickly control such as public information, and to emphasise the responsibility of doctors in recognising cocaine abuse and referring these patients for treatment. J. CAMÍ J. M. ANTÓ J. MONTEIS F. ALVAREZ-LERMA E. MENOYO Institut Municipal d’Investigació Mèdica, F. CAUS and Hospital del Mar, 08003 Barcelona, Spam M. FARRÉ measures,
1. Ghodse AH.
Casualty department and the monitoring of drug dependence. Br Med J 1973; iv: 136-39. 2. Ghodse AH, Edwards G, Stapleton J, et al. Drug-related problems in London accident and emergency departments. Lancet 1981; ii: 859-62. 3. Cami J, Alvarez F, Monteis J, Caus J, Menoyo E, de Torres S. Heroina: Nueva causa de urgencias toxicológicas. Med Clin (Barc) 1984; 82: 1-14. 4. Cami J, Monteis J, Alvarez F, Caus J, Menoyo E, Rodriguez ME. Changing patterns of toxicological emergencies in Barcelona: heroin as a new cause. III World Cong - Fed Assoc Clin Toxicol Poison Control Centres. Brussels, Belgium, 1986.
PSYCHOSIS AND VIOLENCE IN COCAINE SMOKERS ,
SIR,-Epidemic use of "crack", a form of cocaine suitable for smoking, has been reported.1 In the 1970s and early 1980s, individual smokers or "freebasers" had to extract cocaine alkaloid chemically from the hydrochloride. However, in late 1985, pre-processed cocaine alkaloid, known as crack, became available on the streets of New York. An increased frequency of psychiatric problems has been reported in crack users, but symptoms among users of different forms of cocaine have not been compared.2.3 We have reviewed consecutive cases of cocaine abuse presenting to the emergency room in four months in 1985 and in three months in 1986. Demographic variables and symptoms were recorded from histories and mental status examinations. Patients were separated into four groups according to their most recent form of cocaine use: crack, freebase, intravenous, or intranasal. Our impression was that crack smokers presented differently from freebasers,-so they were considered as separate groups. Our sample consisted of 52 men and 28 women, aged 17-45 years (mean 28). About half of all patients admitted marijuana and/or alcohol use in addition, and 5 had a history of psychosis that was not drug-related. Cocaine-related presentations did increase nearly two-fold over the study period, from a mean of 8-5 per month in 1985 to 15per month in 1986. The difference was almost entirely due to crack-related presentations. Of the crack users, 29% required admission compared with 13 % of the other users. The frequency of particular symptoms in each group is shown in the table. For each patient we also totalled the number of symptoms of psychosis and of violence; these scores were then averaged for the groups (table). Significantly more psychotic symptoms and thoughts or acts of violence occurred in the crack group. Interestingly, the presence of psychosis did not significantly correlate with the presence of thoughts or acts of violence
(Spearman r = - 0-04).
*Sigmficant difference among groups (p < 0 05, Kruskal-Wallis). tSignificant difference: crack vs other groups (p < 0-05, Mann-Whitney). tSignificant difference: crack vs other groups (p < 0 01, Mann-Whitney).
The more dramatic manifestations of crack use may be due to the of administration via the lungs which causes a faster rise in plasma cocaine concentration.4 The total dose of cocaine or the frequency of use may be greater for crack; this may account for the differences between crack smokers and freebasers whose dose is limited by laborious manufacture. It is also possible that the differences between groups are not directly due to the form of cocaine use but are due to differences in socioeconomic background, personality characteristics, or expectations of intoxication. Our study has the limitations of being retrospective and based only on non-structured interviews. However, information collected in this fashion is used to make clinical decisions, and our finding of increased psychosis and violence in patients who use crack corresponds with their increased rate of admission. Our results suggest that in the emergency room these patients should receive especially careful evaluation and comprehensive treatment. route
College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA 1.
WILLIAM G. HONER GEORGE GEWIRTZ MAUREEN TUREY
Jekel JF, Allen DF, Podlewski H, Clarke N, Dean-Patterson S, Cartwright P. Epidemic free-base cocaine abuse: Case study from the Bahamas. Lancet 1986; i:
459-62. 2. Washton AM, Gold 1374.
MS, Pottash AC. Intranasal cocaine addiction. Lancet 1983; ii:
3. Washton AM, Gold MS, Pottash AC. Crack. JAMA 1986; 256: 711. 4. Van Dyke C, Byck R. Cocaine. Scientif Am 1982; 246: 128-41.
PRESCRIBING FOR DRUG ADDICTS
SIR,-Several studies have suggested that methadone maintenance is ineffective in the prevention of illicit drug use by addicts (eg, Dobbs,’ Harmoll et aland Kosten et aP). It has also been claimed that prescribed methadone is sold on the black market and abused,1,4,5 but Marks6 has suggested that this does not occur in Liverpool. We can contribute further to this debate with a survey of 5000 urine samples screened for drugs of abuse at the Guy’s Hospital Poisons Unit at New Cross during the first six months of 1987. Urine samples were submitted for screening according to clinical need by general and psychiatric hospitals, as well. as by general practitioners and the local drug dependency units (DDUs). Patients prescribed heroin by the DDUs were excluded from the analysis. 705 of the remaining samples (representing about 355 patients) were
Assuming average courses of chloramphenicol consisted of 250 mg four times daily for five days (about 100 000 g per month = 240 000 courses annually) and between 1 in 50 000 to 1 in 20 000 of those exposed were to acquire aplastic anaemia,1,2 about 5-12 such cases might be expected in Hong Kong every year. Because many of our patients remain unaware of the drugs they take and because
chloramphenicol-induced aplastic anaemia usually presents many months after exposure,1 we assumed that most cases would never be identified as drug associated but that in Hong Kong there might be a high incidence of aplastic anaemia (irrespective of cause) compared with that in countries where little chloramphenicol was sold. However, according to information provided by the Government of Hong Kong Medical and Health Department, death certification for aplastic anaemia averaged 0.4 per 1000 deaths over 1981-85, compared with 1 0 per 1000 deaths in England and Wales.4 Queen Mary Hospital (which deals with over 50 % of the territory’s serious haematological cases) encountered only 6 new cases of aplastic anaemia in 1985, none linked with chloramphenicol. Possible reasons why an excessive incidence of aplastic anaemia has not been recognised in Hong Kong despite the high rate of chloramphenicol sales, include (1) reduced susceptibility to chloramphenicol-induced aplastic anaemia in the local population; (2) missed diagnosis (though it seems unlikely that patients with severe anaemia would not be admitted to hospital and have a bone examination); (3) that contrary to earlier views, irreversible aplastic anaemia is related to dose and duration of therapy so that short courses with low doses (which, presumably, prevail in Hong Kong) are less risky; and (4) hitherto accepted risks of chloramphenicol-induced aplastic anaemia may be exaggerated. Chloramphenicol sales in Hong Kong are unusually high and probably reflect genuine differences in prescribing priorities and consumption. Nevertheless, the incidence of aplastic anaemia in the community does not appear to be unusual. In many developing countries, chloramphenicol is regarded as a cheap and useful drug for the treatment of many infections and in Hong Kong and elsewhere the infecting organism may be resistant to other common
marrow
antimicrobial agents:
Ampuillin Orgamsm Haemophilus influenzae Streptococcus pneumoniae Salmonella typhi
and paratyphz
% zsolates resistant to: Co-trimoxazole Chloramphenicol
Tetracycline
19
1
1
27
0
25
1
70
1
0
0
N/A
N/A not applicable. Source: microbiology department, University Kong, and pharmacy, Queen Mary Hospital.
of
Hong
Prospective investigations are required to re-evaluate the risk of aplastic anaemia -in countries where widespread use of chloramphenicol continues. We thank Prof T. K. Chan for encouragement and useful discussion and helping to trace cases of aplastic anaemia diagnosed in Queen Mary Hospital in 1985; and Mr N. Li (Medical and Health Department) for statistics on certified aplastic anaemia deaths.
C. R. KUMANA
Pharmaceutical Service, Medical and Health Department,
Hong Kong
K. Y. Li
Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Hong Kong
P. Y. CHAN
1. De Gruchy GC. Aplastic anaemia Drug-induced blood disorders. Oxford: Blackwell Scientific Publications, 1975: 39-75. 2. Vincent C. Drug-induced aplastic anaemia and agranulocytosis incidence and mechanisms. Drugs 1986; 31: 52-63. 3. Annual reports of the Hong Kong Medical and Health Department 1981-1985 (table
22). Mortality statistics: Cause 1981-1985, series DH2 (ICD causes) London: HM Stationery Office.
seem to have favourite indoor sports. Cancer and heart disease, obesity and anorexia, and mental illness and drug abuse-we fear them all. But over time we lose interest in one after another and turn our attention to a new peril and a new protection. Now it is AIDS. Everyone is at risk. The disease is so contagious that some medical personnel and undertakers refuse to care for and bury the victims. It is so costly that soon it will bankrupt us. Such are the claims. What is there to do? Spend more on research; test immigrants and even tourists; quarantine homosexuals; give addicts free needles? Such are the proferred solutions. Let us try to look at AIDS through the lens of history instead of hysteria. When the US Surgeon General compares AIDS to the Black Death, he may be on to something neither he nor the American people are prepared to face. For who (except some historians) now realises that the Black Death killed one-third of Europe’s population because, in the absence of cats, rats multiplied and spread the plague? Why were there no cats? Because there was a war on witches, and cats, being the witches’ helpers, were exterminated. The spread of AIDS is now due, at least in part, to addicts’ use of dirty needles. Why are there suddenly so many dirty needles around? Because there is a war on drugs, and needles, being the addicts’ helpers, are outlawed. One-quarter or more of all AIDS victims in the United States are addists. Half of New York City’s 200 000 heroin addicts are said to carry HIV. Their sexual contacts transmit the virus to the heterosexual population. If drugs and needles could be bought like beer and beer glasses addicts would not need to use dirty needles. Suppose that a remedy were at hand that would virtually guarantee to reduce the incidence of AIDS overnight by at least one-third; that the remedy were medically safe (ie, it would produce no biologically deleterious side-effects); and that it would cost us nothing, would save us vast sums expended on law enforcement, and would make our homes and streets safer. Would this remedy be embraced as a godsend--or would it be rejected as the very handiwork of the devil? The facts speak for themselves--and what they tell us is disheartening. Politicians pontificate about the free market to protect American exports, such as cigarettes, but consider it anathema even to contemplate a free market in drugs. Would such a policy increase heroin addiction in exchange for a decreased incidence of AIDS? Perhaps. Perhaps not. In any case, were drugs and needles available like beer and beer glasses, how many Americans would want to inject heroin into their bodies? I doubt that the number is as dangerously great as the threat posed by AIDS.
SIR,-Fearing health hazards and fighting them
become
’
our
University Hospital, Department of Psychiatry, SUNY Health Science Center, Syracuse, NY13210, USA
THOMAS S. SZASZ
MONITORING COCAINE EPIDEMICS IN BARCELONA
SiR,—The monitoring of drug-related problems in emergency is a good indicator for epidemiological surveillance of drug dependence.1,2 This system can detect increases in drug abuse prevalence as well as sudden changes in patterns of abuse. Since 1979, in the Hospital del Mar, Barcelona, we have monitored toxicological emergencies. We detected a sudden rise in heroin-related casualties in December, 1981, preceding a large and steady increase in admissions to opioid-treatment faCilitiM3In October, 1986, a sudden increase of cocaine-admissions was
rooms
Department of Medicine, University of Hong Kong, Queen Mary Hospital, Hong Kong
4.
AIDS AND DRUGS: BALANCING RISK AND BENEFITS
no
284 and deaths from all
detected. The number of casualties has remained increased since (figure). A major proportion of these cocaine-related problems comes from its intranasal use. During the past year, 57% of cocaine-related admissions were because of withdrawal problems, 24% were overdoses, and 19% were because of ’other complications. In contrast, heroin-related emergencies have remained stable at a mean of 225 per month.4 These fmdings indicate that a large increase of cocaine consumption occurs in Barcelona in groups other than intravenous drug abusers. This signal, found in a simple monitoring system,
451 PERCENTAGE
FREQUENCY OF OCCURRENCE OF PSYCHIATRIC
SYMPTOMS AND VIOLENCE IN DIFFERENT GROUPS OF COCAINE USERS
Quarterly
mean
of cocaine-related
emergencies
in
Hospital del
Mar, Barcelona. should allow the municiple authorities to undertake quickly control such as public information, and to emphasise the responsibility of doctors in recognising cocaine abuse and referring these patients for treatment. J. CAMÍ J. M. ANTÓ J. MONTEIS F. ALVAREZ-LERMA E. MENOYO Institut Municipal d’Investigació Mèdica, F. CAUS and Hospital del Mar, 08003 Barcelona, Spam M. FARRÉ measures,
1. Ghodse AH.
Casualty department and the monitoring of drug dependence. Br Med J 1973; iv: 136-39. 2. Ghodse AH, Edwards G, Stapleton J, et al. Drug-related problems in London accident and emergency departments. Lancet 1981; ii: 859-62. 3. Cami J, Alvarez F, Monteis J, Caus J, Menoyo E, de Torres S. Heroina: Nueva causa de urgencias toxicológicas. Med Clin (Barc) 1984; 82: 1-14. 4. Cami J, Monteis J, Alvarez F, Caus J, Menoyo E, Rodriguez ME. Changing patterns of toxicological emergencies in Barcelona: heroin as a new cause. III World Cong - Fed Assoc Clin Toxicol Poison Control Centres. Brussels, Belgium, 1986.
PSYCHOSIS AND VIOLENCE IN COCAINE SMOKERS ,
SIR,-Epidemic use of "crack", a form of cocaine suitable for smoking, has been reported.1 In the 1970s and early 1980s, individual smokers or "freebasers" had to extract cocaine alkaloid chemically from the hydrochloride. However, in late 1985, pre-processed cocaine alkaloid, known as crack, became available on the streets of New York. An increased frequency of psychiatric problems has been reported in crack users, but symptoms among users of different forms of cocaine have not been compared.2.3 We have reviewed consecutive cases of cocaine abuse presenting to the emergency room in four months in 1985 and in three months in 1986. Demographic variables and symptoms were recorded from histories and mental status examinations. Patients were separated into four groups according to their most recent form of cocaine use: crack, freebase, intravenous, or intranasal. Our impression was that crack smokers presented differently from freebasers,-so they were considered as separate groups. Our sample consisted of 52 men and 28 women, aged 17-45 years (mean 28). About half of all patients admitted marijuana and/or alcohol use in addition, and 5 had a history of psychosis that was not drug-related. Cocaine-related presentations did increase nearly two-fold over the study period, from a mean of 8-5 per month in 1985 to 15per month in 1986. The difference was almost entirely due to crack-related presentations. Of the crack users, 29% required admission compared with 13 % of the other users. The frequency of particular symptoms in each group is shown in the table. For each patient we also totalled the number of symptoms of psychosis and of violence; these scores were then averaged for the groups (table). Significantly more psychotic symptoms and thoughts or acts of violence occurred in the crack group. Interestingly, the presence of psychosis did not significantly correlate with the presence of thoughts or acts of violence
(Spearman r = - 0-04).
*Sigmficant difference among groups (p < 0 05, Kruskal-Wallis). tSignificant difference: crack vs other groups (p < 0-05, Mann-Whitney). tSignificant difference: crack vs other groups (p < 0 01, Mann-Whitney).
The more dramatic manifestations of crack use may be due to the of administration via the lungs which causes a faster rise in plasma cocaine concentration.4 The total dose of cocaine or the frequency of use may be greater for crack; this may account for the differences between crack smokers and freebasers whose dose is limited by laborious manufacture. It is also possible that the differences between groups are not directly due to the form of cocaine use but are due to differences in socioeconomic background, personality characteristics, or expectations of intoxication. Our study has the limitations of being retrospective and based only on non-structured interviews. However, information collected in this fashion is used to make clinical decisions, and our finding of increased psychosis and violence in patients who use crack corresponds with their increased rate of admission. Our results suggest that in the emergency room these patients should receive especially careful evaluation and comprehensive treatment. route
College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA 1.
WILLIAM G. HONER GEORGE GEWIRTZ MAUREEN TUREY
Jekel JF, Allen DF, Podlewski H, Clarke N, Dean-Patterson S, Cartwright P. Epidemic free-base cocaine abuse: Case study from the Bahamas. Lancet 1986; i:
459-62. 2. Washton AM, Gold 1374.
MS, Pottash AC. Intranasal cocaine addiction. Lancet 1983; ii:
3. Washton AM, Gold MS, Pottash AC. Crack. JAMA 1986; 256: 711. 4. Van Dyke C, Byck R. Cocaine. Scientif Am 1982; 246: 128-41.
PRESCRIBING FOR DRUG ADDICTS
SIR,-Several studies have suggested that methadone maintenance is ineffective in the prevention of illicit drug use by addicts (eg, Dobbs,’ Harmoll et aland Kosten et aP). It has also been claimed that prescribed methadone is sold on the black market and abused,1,4,5 but Marks6 has suggested that this does not occur in Liverpool. We can contribute further to this debate with a survey of 5000 urine samples screened for drugs of abuse at the Guy’s Hospital Poisons Unit at New Cross during the first six months of 1987. Urine samples were submitted for screening according to clinical need by general and psychiatric hospitals, as well. as by general practitioners and the local drug dependency units (DDUs). Patients prescribed heroin by the DDUs were excluded from the analysis. 705 of the remaining samples (representing about 355 patients) were