Safety Comparison: Allopathic vs. Chiropractic Healthcare

All healthcare disciplines are associated with risks of injury or death. Rare but sensational occurrences are often exploited by the media, leading the public to believe that rare events are commonplace. In contrast, common occurrences are often under reported, leading the public to have higher confidence in the safety of certain healthcare disciplines and procedures.

How Safe Is Medical Care?

The risks of medical healthcare (allopathic healthcare) were shockingly revealed in 1994 when Harvard’s Lucian Leape, MD, indicated that medical error was responsible for 180,000 deaths per year (1, 2). Dr. Leape’s analogy was that this was “the equivalent of three jumbo-jet crashes every 2 days,” killing all on board (2). Dr. Leape’s revelation was published in the prestigious Journal of the American Medical Association, and titled:

Error in Medicine

Four years after Dr. Leape’s headlines pertaining to error in medicine, Jason Lazarou, MD (neurologist) and colleagues from the University of Toronto published a study in the Journal of the American Medical Association titled (3):

Incidence of Adverse Drug Reactions in Hospitalized Patients

A Meta-analysis of Prospective Studies

The objective of this study was to estimate the incidence of serious and fatal adverse drug reactions (ADR) in hospital patients. Serious ADRs were defined as those that required hospitalization, were permanently disabling, or resulted in death. The authors performed a meta-analysis of 39 prospective studies done in the United States over a period of 32 years on the incidences of Adverse Drug Reactions (ADRs). The goal of this study was to “estimate injuries incurred by drugs that were properly prescribed and administered.” If the event was determined to be a “Possible ADRs” it was excluded from this study. The authors noted:

“We estimated that in 1994 overall 2,216,000 (1,721,000-2,711,000) hospitalized patients had serious ADRs and 106,000 (76,000-137,000) had fatal ADRs, making these reactions between the fourth and sixth leading cause of death.”

“We have found that serious ADRs are frequent and more so than generally recognized. Fatal ADRs appear to be between the fourth and sixth leading cause of death. Their incidence has remained stable over the last 30 years.”

“It is important to note that we have taken a conservative approach, and this keeps the ADR estimates low by excluding errors in administration, overdose, drug abuse, therapeutic failures, and possible ADRs. Hence, we are probably not overestimating the incidence of ADRs.”

This study on ADRs excluded medication errors “to show that there are a large number of serious ADRs even when the drugs are properly prescribed and administered.”

“The incidence of serious and fatal ADRs in US hospitals was found to be extremely high.”

The incidence of hospital adverse drug reactions detailed in the Lazarou and colleague’s study is stunning:

Importantly, these numbers require additional discussion. These statistics pertain only to hospitalized patients; they did not assess similar such events occurring outside of the hospital setting, in locations such as nursing homes, extended care facilities, at home, etc.

Additionally, and more startling, these deaths and serious adverse events occurred as a consequence of taking the correct drug for the correct diagnosis in the correct dosage. As such, these deaths and serious adverse events are not considered to be as a consequence of error. Rather, they are considered to be “fallout” of a health care delivery discipline that is heavily dependent upon pharmacology.

Dr. Leape’s premise of “Error in Medicine” was updated in 2016, showing that the problem has not improved in the past two decades. Published in the British Medical Journal, Johns Hopkins University School of Medicine professor Martin A. Makary (MD, MPH) and research fellow Michael Daniel (medical student) produced an article titled (4):

Medical Error

The Third Leading Cause of Death in the United States

This title is misleading, and lay publications were mislead into believing that medical error was the 3rd leading cause of yearly death in the United States. The article clearly notes that the 3rd leading cause of death in the United States is error in hospitals. Once again, the data did not assess medical error deaths occurring outside of the hospital setting, in nursing homes, extended care facilities, at home, etc. Nor did it assess “fallout” deaths either in the hospital or outside the hospital setting.

In this study, Makary and Daniel analyzed the scientific literature on hospital medical errors to identify its contribution to US deaths. In their appraisal of the magnitude of the problem, they note:

“We calculated a mean rate of death from [hospital] medical error of 251,454 a year.”

“We believe this understates the true incidence of death due to medical error because the studies cited rely on errors extractable in documented health records and include only inpatient deaths.”

[Hospital] “medical error is the third biggest cause of death in the US and therefore requires greater attention.”

As noted, the 251,000 deaths from medical error underestimates the actual number because it represents only medical error deaths that occur in the hospital setting. Medical error deaths occurring in non-hospital facilities or at home are not included in the estimated number.


How Safe Are Pain Medications?

The primary reason people seek chiropractic care is for pain. Chiropractic is considered an alternative therapy for pain management, and especially for spinal pain (5, 6). An important study looking at some of the risks associated with the chronic use of nonsteroidal anti-inflammatory drugs (NSAIDs) for pain was published by M. Michael Wolfe, MD, and colleagues, from Stanford’s Medical School and Boston University School of Medicine, and published in the New England Journal of Medicine in 1999. The article was titled (7):

Gastrointestinal Toxicity of

Nonsteroidal Anti-inflammatory Drugs

The authors make the following points:

“It has been estimated conservatively that 16,500 NSAID-related deaths occur among patients with rheumatoid arthritis or osteoarthritis every year in the United States.”

“If deaths from gastrointestinal toxic effects of NSAIDs were tabulated separately in the National Vital Statistics reports, these effects would constitute the 15th most common cause of death in the United States.”

“Yet these toxic effects remain largely a ‘silent epidemic,’ with many physicians and most patients unaware of the magnitude of the problem.”

“Furthermore, the mortality statistics do not include deaths ascribed to the use of over-the-counter NSAIDs.”

The authors note that Cox-2 inhibitors (a prescription form of NSAID) have been available in the US since February 1999, in the hope that they will have a reduced capacity to cause injury to the gastroduodenal mucosa. However, Cox-2 inhibitors are also known to cause defects in renal function, alter the regulation of bone resorption, impair female reproductive physiology, and increase the rate of thrombotic events in patients with increased risk of cardiovascular disease.

In 2003, researchers from the University of Queensland, Australia, published a study in the Journal Spine, titled (8):

Chronic Spinal Pain:

A Randomized Clinical Trial Comparing

Medication, Acupuncture, and Spinal Manipulation

In this study, the spinal manipulation was performed by licensed chiropractors (two visits per week). The medications used were Celebrex or Vioxx, both prescription NSAIDs. The acupuncture (also two visits per week) was performed by an experienced acupuncturist. The study evaluated 115 chronic neck and back pain patients. The treatment interventions extended over a 9-week period. These authors made the following observations and statements:

“Adverse reactions to nonsteroidal antiinflammatory (NSAID) medication have been well documented.”

“Gastrointestinal toxicity induced by NSAIDs is one of the most common serious adverse drug events in the industrialized world.”

“The newer COX-2-selective NSAIDs are less than perfect, so it is imperative that contraindications be respected.”

There is “insufficient evidence for the use of NSAIDs to manage chronic low back pain.”

“The highest proportion of early (asymptomatic status) recovery was found for manipulation (27.3%), followed by acupuncture (9.4%) and medication (5%).”

“Manipulation yielded the best results over all the main outcome measures.”

“The consistency of the results provides evidence that in patients with chronic spinal pain, manipulation, if not contraindicated, results in greater short-term improvement than acupuncture or medication.”

“The results of this efficacy study suggest that spinal manipulation, if not contraindicated, may be superior to needle acupuncture or medication for the successful treatment of patients with chronic spinal pain syndrome.”

“Medication apparently did not achieve a marked improvement in chronic spinal pain and caused adverse reactions in 6.1% of the patients.”

“In summary, the significance of the study is that for chronic spinal pain syndromes, it appears that spinal manipulation provided the best overall short-term results, despite the fact that the spinal manipulation group had experienced the longest pretreatment duration of pain.”

Highlights of this study show that chiropractic spinal manipulation is five times more effective than prescription NSAIDs in the treatment of chronic low back and neck pain, and the results from spinal manipulation were accomplished without any reported adverse events. In contrast, for the patients taking the drugs, more experienced an adverse event (6.1%) than those who became asymptotic (5%) over the nine-week clinical trial.

Importantly, when this study was published in 2003, Vioxx had been on the market since 1999, four years. The following year, 2004, Vioxx was pulled off the market due to an unacceptable incidence of fatal heart attacks and strokes (9, 10). It has since been established that in the five years that Vioxx was on the market it caused more US deaths (about 60,000) than the Viet Nam war did in 10 years (about 58,000).

How Safe Is Chiropractic?

The most sensational adverse event with a supposed link to chiropractic spinal manipulation is vertebral artery dissection. Allegations of vertebral artery dissection caused by chiropractic spinal manipulation have appeared in the published literature for decades. However, recent large critical reviews of the topic have appeared in the scientific literature, and they question the causation between cervical spine manipulation and cervical artery dissection. Some of this literature is reviewed below.


In 2008, Dr. David Cassidy and colleagues published the most comprehensive study at that time pertaining to the risk of vertebral artery dissection as related to chiropractic cervical spine manipulation. The article was published in the journal Spine, and titled (11):

Risk of Vertebrobasilar Stroke and Chiropractic Care:

Results of a Population-Based Case-Control and Case-Crossover Study

This study included all residents of Ontario, CAN, over a period of 9 years, amounting to 109,020,875 person years of observation. Associations between chiropractic visits and vertebral artery dissection versus primary care physician (PCP) visits and vertebral artery dissection were compared.

The authors noted:

“We found no evidence of excess risk of vertebral artery stroke associated with chiropractic care.”

“Neck pain and headache are common symptoms of vertebral artery dissection, which commonly precedes vertebral artery stroke.”

“The increased risks of vertebral artery stroke associated with chiropractic and primary care physicians visits is likely due to patients with headache and neck pain from vertebral artery dissection seeking care before their stroke.”

“Because patients with vertebrobasilar artery dissection commonly present with headache and neck pain, it is possible that patients seek chiropractic care for these symptoms and that the subsequent vertebral artery stroke occurs spontaneously, implying that the association between chiropractic care and vertebral artery stroke is not causal.”

“Our results suggest that the association between chiropractic care and vertebral artery stroke found in previous studies is likely explained by presenting symptoms attributable to vertebral artery dissection.”


In January of 2011, the Journal of Manipulative and Physiological Therapeutics published a population-based case series using administrative health care records of all Ontario, CAN, residents hospitalized with vertebral artery stroke between April 1, 1993, and March 31, 2002, titled (12):

A Population-based Case-series of Ontario Patients who

Develop a Vertebrobasilar Artery Stroke After Seeing a Chiropractor

These authors note:

“The current evidence suggests that association between chiropractic care and vertebrobasilar artery (VBA) stroke is not causal. Rather, recent epidemiological studies suggest that it is coincidental and reflects the natural history of the disorder.”

“Because neck pain and headaches are symptoms that commonly precede the onset of a VBA stroke, these patients might seek chiropractic care while their stroke is in evolution.”