Statement of Principles concerning portal vein thrombosis (Reasonable Hypothesis) (No. 107 of 2022)

The central concept is “reasonable hypothesis”, a standard of proof used in the military compensation and veterans’ entitlements systems. It is lower than the civil standard of reasonable satisfaction: a hypothesis is reasonable if there is some medical‑scientific evidence to support it, even if it is not the most probable explanation. The RMA’s view, stated in section 7, is that there is sound medical‑scientific evidence indicating that portal vein thrombosis and death from it can be related to relevant service. The instrument does not define “reasonable hypothesis” itself; that is established by case law under the VEA. Second, “portal vein thrombosis” is defined narrowly: it is a blood clot within the portal vein, and includes pylephlebitis (inflammation and thrombosis of the portal vein). The exclusion of vaccine-induced thrombotic thrombocytopaenia (VITT) is significant because it removes a link for persons who developed portal vein thrombosis after receiving a COVID-19 vaccine; that mechanism is not accepted under this SOP. The exclusion of intentional embolisation is straightforward. Third, the “factors” in section 8 are the key building blocks. They fall into categories: pre-existing medical conditions (e.g., cirrhosis, hypercoagulable state, intra-abdominal malignant neoplasm, myeloproliferative neoplasm, autoimmune disease, chronic hepatitis B or C, active tuberculosis, obesity); temporal events (e.g., abdominal surgery within 6 months, blunt trauma within 30 days, altitude exposure for 28 days, underwater diving within 24 hours, SARS‑CoV‑2 infection within 2 months, cytomegalovirus infection within 30 days, foreign body penetration within 30 days); medication or substance use (drugs from the specified list within 30 days, didanosine for at least 3 years); mechanical factors (compression of the portal vein, infection or inflammation involving the portal vein or contiguous tissue); and treatment factors (liver or stem cell transplant within 2 months, inability to obtain appropriate clinical management). The dictionary defines key concepts: “hypercoagulable state” means an increased propensity to venous thrombosis due to an abnormality in the coagulation system, with examples including antiphospholipid syndrome, nephrotic syndrome and paroxysmal nocturnal haemoglobinuria. “Being obese” uses either a BMI of 30 or greater, or a waist circumference exceeding 102 cm (males) or 88 cm (females). The “specified list of autoimmune diseases” is limited to just four conditions: autoimmune hepatitis, eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome), inflammatory bowel disease, and systemic lupus erythematosus. The “specified list of drugs” includes five categories: combined oral contraceptive pill, menopausal hormone therapy, protease inhibitors, testosterone, and thrombopoietin receptor agonists. “Terminal event” is defined as the proximate or ultimate cause of death and includes pneumonia, respiratory failure, cardiac arrest, circulatory failure, or cessation of brain function.

This SOP directly affects veterans, members of Peacekeeping Forces, and members of the Forces under the VEA, as well as members under the MRCA who have rendered relevant service as defined in the Schedule 1. “Relevant service” includes operational service, peacekeeping service, hazardous service, British nuclear test defence service under the VEA, and warlike or non-warlike service under the MRCA. This is the group of people who can claim compensation for portal vein thrombosis. Because portal vein thrombosis can be asymptomatic (as noted in the instrument) or have late clinical manifestations, many potential claimants may not know they have the condition. The SOP affects their ability to establish a reasonable hypothesis. Secondary affected persons include dependants or estate claimants where death from portal vein thrombosis is involved. The SOP also binds decision-makers at the Department of Veterans’ Affairs and the Military Rehabilitation and Compensation Commission. They must apply section 8 factors when assessing claims. Medical practitioners providing opinions on connection to service must work within the definitions and factors. The SOP creates a clear framework but also imposes a compliance burden: to raise a reasonable hypothesis, the claimant must produce evidence satisfying at least one factor and that the factor is related to service. For example, if a veteran had abdominal surgery within 6 months before clinical onset, that surgery must be connected to service. If the surgery was for a service-related condition, it is easier; if it was elective private surgery, it may not be related. The instrument also affects the RMA itself, which has ongoing obligations under the VEA to keep SOPs up to date. This SOP replaces any earlier SOP on portal vein thrombosis. For legal practitioners and advocates representing veterans, the SOP provides a checklist of potential causal pathways. For government, the SOP standardises decision-making, reducing discretion but also potentially limiting claims if the facts do not match a listed factor.

This SOP does not impose duties on individuals in the way a regulatory law might. Instead, it creates a path of rights for claimants to have their claim assessed under a reasonable hypothesis standard. A claimant has the right to rely on any one of the 21 factors in section 8 to raise a reasonable hypothesis, provided the factor is related to their service under section 9. The decision-maker has a duty to consider the SOP when determining whether a reasonable hypothesis exists. Under section 120A of the VEA, the SOP is binding on the decision-maker: if the material raises a hypothesis that fits one of the factors, and the factor is related to service, the hypothesis is taken to be reasonable unless there is contrary proof. The RMA has a duty under the VEA to determine SOPs based on sound medical‑scientific evidence; section 7 states that the RMA is of the view that such evidence exists for portal vein thrombosis. However, the instrument itself does not create a duty to update or review; that duty comes from the parent Act. The SOP also imposes interpretive duties on decision-makers: they must apply the definitions in Schedule 1 strictly. For example, “being obese” must be assessed using BMI or waist circumference thresholds, not general clinical judgment. The right to rely on factor 21 (inability to obtain appropriate clinical management) is limited by section 9(2): it only applies to material contribution to or aggravation of a pre-existing portal vein thrombosis that did not arise out of service. This means that a veteran who already had portal vein thrombosis and whose service made it worse through lack of clinical management can use this factor; but a person who developed portal vein thrombosis de novo during service cannot use that factor if the condition itself arose out of service. There is also a duty to apply section 10, which says that if a factor refers to another injury or disease that is itself covered by another SOP, then the factors in that other SOP also apply. For instance, factor 1 requires “cirrhosis of the liver”. Cirrhosis is itself a disease likely covered by its own SOP. The decision-maker must then apply the cirrhosis SOP as well. This creates an interlocking web of factors. The claimant does not have to prove the entire chain; the SOP system allows a cascade of reasonable hypotheses.

This instrument contains no penalties. It is not a penal or regulatory instrument; it is a standard-setting legislative instrument used in the assessment of compensation claims. The enforcement mechanism is indirect: if a decision-maker fails to properly apply the SOP, the claimant can seek review by the Veterans’ Review Board, the Administrative Appeals Tribunal (AAT), and ultimately the Federal Court. A decision that is inconsistent with the SOP can be set aside. There are no fines or criminal sanctions. The only “penalty” for the government is having to pay compensation that might otherwise be denied if the SOP is incorrectly applied. For claimants, there is no penalty for raising a hypothesis that does not fit the factors; the claim is simply rejected. However, if a claimant knowingly makes a false statement in relation to a factor, they could face penalties under the VEA or Criminal Code for fraud, but that is not specific to this SOP. The instrument itself does not create any offences. The RMA is not subject to penalties for failing to update the SOP, but the VEA does require the Authority to review SOPs periodically. The practical effect of enforcement is through the standard of proof. The SOP lowers the standard for claimants to “reasonable hypothesis” from the higher “reasonable satisfaction”. By specifying factors, it makes enforcement of the standard more predictable. If a factor is present, and related to service, the decision-maker must accept the hypothesis as reasonable unless there is evidence that disproves it. That is a significant pro‑claimant feature. Conversely, if no factor is present, the decision-maker can reject the hypothesis without needing to weigh evidence against it, which streamlines rejections.

The SOP sits within the framework of the Veterans’ Entitlements Act 1986 and the Military Rehabilitation and Compensation Act 2004. Specifically, it is made under subsection 196B(2) of the VEA. It applies to claims to which section 120A of the VEA or section 338 of the MRCA apply. Section 120A of the VEA provides that the standard of proof for determining whether an injury or disease is related to service is a reasonable hypothesis, and that the RMA’s Statements of Principles are binding on that determination. This means the SOP is conclusive on what factors can raise a reasonable hypothesis. Section 7 of the instrument states the RMA’s view that sound medical‑scientific evidence exists, which is a jurisdictional precondition. The SOP interacts with other SOPs through section 10: if a factor refers to another injury or disease for which a SOP exists, that other SOP’s factors apply as in force from time to time. For example, factor 6 refers to “autoimmune disease from the specified list”. The listed diseases include inflammatory bowel disease, which itself may be covered by an SOP. When assessing whether a person has that autoimmune disease, the decision-maker must apply the definition in that disease’s SOP, not a general medical definition. This creates an embedded reference system that can cascade across multiple SOPs. The instrument also defines terms like “relevant service” by reference to the VEA and MRCA. It does not override the VEA or MRCA; it supplements them. It does not interact with state workers’ compensation laws or private insurance; it is specific to Commonwealth military compensation. The exclusion of vaccine-induced thrombotic thrombocytopaenia in section 6(2)(b) means that any claim based on a COVID-19 vaccine injury will not be assessed under this SOP. However, other SOPs may cover that condition. The instrument also has a note referencing terminal event and death: it includes death contributed to by portal vein thrombosis. That brings in the VEA’s provisions on dependency claims. The SOP does not touch the Safety, Rehabilitation and Compensation (Defence-related Claims) Act 1988, which applies to some defence civilians. Claimants under that Act would use different provisions. The instrument also interacts with the Evidence Act 1995 indirectly through the AAT. Overall, the SOP is a subordinate legislative instrument that controls the evidentiary standard for a specific condition within a broader statutory compensation scheme.

This instrument is a new SOP: Statement of Principles concerning portal vein thrombosis (Reasonable Hypothesis) (No. 107 of 2022). It was made on 21 October 2022 and commences on 21 November 2022. The instrument does not state that it revokes an earlier SOP, but it is standard practice for the RMA to issue new SOPs that supersede previous ones. Typically, the RMA issues a replacement SOP when new medical‑scientific evidence becomes available or when the existing SOP is due for review under the VEA’s statutory review cycle. The previous SOP on portal vein thrombosis was likely No. 97 of 2014 (or a similar number), but the instrument itself does not name it. The RMA sometimes issues a Statement of Principles in two versions: “Reasonable Hypothesis” (for operational service) and “Balance of Probabilities” (for non‑operational service). This one is the Reasonable Hypothesis version. There is probably a corresponding Balance of Probabilities SOP (No. 108 of 2022) made under subsection 196B(3) of the VEA. The instrument includes no amendment history within its text, as it is the original version. The SOP is not a regulation that gets amended multiple times; typically a new SOP replaces the old one entirely. Future amendments will come via a new SOP number. The VEA requires the RMA to keep SOPs under review; the frequency is not fixed but usually every 5 to 10 years. Practitioners should check that they are using the current SOP number. As at the date of this deep dive, No. 107 of 2022 is the current version. The instrument has no transitional provisions; it applies from its commencement date to claims made after that date, but also to claims made before commencement that have not been finally determined, by operation of section 120A of the VEA (as interpreted by case law). The amendment history is thus minimal: one instrument made in 2022, no amending instruments registered.

The instrument itself does not cite any cases, and the deep dive cannot invent litigation. However, the broader context is that Statements of Principles are frequently litigated in the AAT and Federal Court. The typical issues are: whether a hypothesis is reasonable given the factors; whether the evidence supports the existence of a factor; and whether the factor is related to service. The definitional sections, especially “hypercoagulable state” and “specified list of autoimmune diseases”, have been subject to interpretive disputes in other SOP contexts. For example, in cases involving other clotting conditions, the AAT has examined whether a particular medical condition falls within the definition of hypercoagulable state. The exclusion of VITT may generate litigation if a claimant argues that the RMA applied the wrong test in excluding it. But that would be a challenge to the validity of the SOP under the VEA, not an application of it. The RMA’s view in section 7 is stated but could be challenged on judicial review if it can be shown there is no sound medical‑scientific evidence. However, courts give the RMA a wide margin of appreciation. The Federal Court has held that the RMA’s determination is not subject to merits review. Litigation under the specific SOP will arise as claims are decided. Because portal vein thrombosis is a relatively uncommon condition, the volume of cases is likely low. The instrument’s detailed list of factors reduces the scope for argument compared to a generic SOP. Notably, factor 5 (altitude of at least 3,000 metres for 28 days) is unusual and may generate litigation if a claimant’s service included high-altitude operations (e.g., in mountainous regions). Factor 18 (underwater diving within 24 hours) is also unusual. Cases may turn on whether “continuous period” includes partial days. The definition of “being obese” with specific measurements may also be litigated, especially for claimants who do not have weight recorded at the time of clinical onset. The litigation history will develop over time, but as of the instrument’s commencement, there are no decisions specifically on this SOP. The deep dive cannot cite any.

Several provisions in this SOP are easy to overlook or misinterpret. First, the exclusion of vaccine-induced thrombotic thrombocytopaenia (VITT) in section 6(2)(b) means that any portal vein thrombosis arising from a COVID-19 vaccine cannot be linked to service via this SOP. This could be a trap for claimants who developed the condition after receiving a vaccine during service. Second, factor 5 requires being at an altitude of at least 3,000 metres for a continuous period of at least the 28 days before clinical onset. The word “continuous” is strict; a day spent below 3,000 metres during that period could break the factor. Service personnel on short patrols in high-altitude areas may not meet the continuous requirement. Third, factor 18 (underwater diving with compressed air within 24 hours) is a very short window. It does not apply to free diving or snorkelling, only compressed air diving. Fourth, the definition of “hypercoagulable state” is limited to an abnormality in the coagulation system. Common conditions like pregnancy, cancer, or recent surgery may cause hypercoagulability but are not covered unless they result from an abnormality in the coagulation system itself. The note lists antiphospholipid syndrome, nephrotic syndrome and paroxysmal nocturnal haemoglobinuria as examples; other conditions may not qualify. Fifth, the “specified list of autoimmune diseases” is narrow (four diseases). Many autoimmune conditions, such as rheumatoid arthritis or Sjögren’s syndrome, are not listed and cannot be used unless they cause a hypercoagulable state under factor 2 or another factor. Sixth, the drug list in factor 7 includes “protease inhibitors” without specifying which. This could be interpreted broadly (HIV protease inhibitors, HCV protease inhibitors) or narrowly. The definition only cross-references the drug list; it does not define the term “protease inhibitors” itself. Seventh, factor 21 (inability to obtain appropriate clinical management) is limited by section 9(2) to aggravation or material contribution of pre-existing portal vein thrombosis not arising from service. It cannot be used for a condition that arose out of service or for the initial onset. Eighth, the definition of “being obese” uses BMI or waist circumference. Waist circumference is often not recorded in medical records, creating an evidence gap. Ninth, factor 4 (abdominal surgery) includes “endoscopic treatment of gastro-oesophageal varices” as an example. That is not obviously surgery but is included. Tenth, factor 16 (foreign body penetration or occlusion) examples include fish bones, toothpicks, and metal wires. For a service claim, the foreign body must be related to service. A veteran who eats a fish bone during a meal on base may have difficulty showing service relationship unless the meal was part of operations. Finally, section 10 creates a hidden trap: if a factor refers to another disease covered by a SOP, that SOP’s factors apply. So a claimant relying on factor 1 (cirrhosis) must also satisfy the cirrhosis SOP factors. This can add complexity.

For a legal practitioner or advocate preparing a claim for portal vein thrombosis, compliance with this SOP means gathering evidence to show that at least one factor from section 8 existed at the time of clinical onset and that the factor is related to the person’s relevant service under section 9. The first step is to obtain a definitive diagnosis of portal vein thrombosis as defined in section 6(2). The diagnosis must exclude intentional embolisation and VITT. If the diagnosis is unclear, a specialist opinion may be needed. Second, identify the date of clinical onset. The instrument does not define “clinical onset”, but it is the time when symptoms or signs first appear that would lead to diagnosis. For asymptomatic cases detected incidentally, clinical onset may be the date of imaging. Third, check each factor against the facts. Useful factors for military service may include: blunt trauma to the abdomen (factor 17) from combat or training; altitude exposure (factor 5) for high-altitude operations; infection (factors 10, 12, 13, 14, 15) if the person contracted relevant infections during service; and obesity (factor 19) if service-related weight gain meets the thresholds. Factor 2 (hypercoagulable state) requires objective evidence of a coagulation abnormality; factor tests such as lupus anticoagulant or protein C/S levels may be needed. Factor 6 (autoimmune disease) requires a diagnosed listed autoimmune disease. Factor 7 (drugs) requires evidence of taking a listed drug within 30 days before onset. The drug must be from the limited list: note that factor 7 says “taking a drug from the specified list of drugs within the 30 days” - this is a single dose exposure? The instrument allows any amount within the 30 days. Didanosine (factor 8) requires at least 3 years of use, which is a high threshold and may be relevant to HIV-positive veterans. Factor 4 (abdominal surgery) requires proof of service related surgery within 6 months. Factor 9 (compression) requires imaging evidence. Factor 10 (infection/inflammation involving contiguous tissue) requires contemporaneous diagnosis of conditions like pancreatitis or diverticulitis. For death claims, the terminal event definition applies; a death certificate should be obtained. Section 9(1) requires that the factor itself be related to service. For example, if the factor is obesity, the obesity must be due to service factors (e.g., inactivity from service injury). The instrument does not say the factor must be caused by service; it says “must be related to the relevant service”. That is a looser connection than causation, but still requires a service link. Advocates should obtain medical evidence that the factor is present and provide a written submission explaining how it relates to service. Section 10 requires checking if any referenced disease has its own SOP; if so, ensure that SOP’s factors are also met. Finally, keep a copy of the current SOP (No. 107 of 2022) and note its commencement date. Claims made before 21 November 2022 may have been assessed under the previous SOP. For decision-makers, compliance means applying the factors strictly, not adding or subtracting. If no factor is present, the claim must be rejected on the basis that no reasonable hypothesis is raised. If a factor is present but not related to service, the claim must also be rejected. The instrument is a closed list; creative hypotheses not on the list are not sufficient.